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Discussion and technical support related to USRP, UHD, RFNoC
View all threadsRe: NIC suggestion
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link to support
that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936 Kbps, 16 *
19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use their OFED
drivers:(
On a related question. it seems that the streamer doesn't crash anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no conversion
required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work as far as I
can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format =
"sc16",
.otw_format =
"sc16",
.args = "",
.n_channels =
1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode
= UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now
= true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL, LN,
FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0], &maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d). %s.\n", 0,
FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0, FL,
LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err = uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL, LN,
FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err = uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d). %s.\n",
0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN, FN,
err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n", 0, FL,
LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN, FN,
channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0, &tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d).
%s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate /
if (srate && !uhd_set_rx_rate_check(channel, srate)) return(FAIL);
/ Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain, channel, "")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db (%d).
%s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel], channel, "",
&tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n", 0,
channel, tmp, gain);
./* Set channel bw to conserve tuner resources. Not needed, set by
srate /
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./ Disable subtracting constant averaged background. Signal looks
cleaner */
if ((err = uhd_usrp_set_rx_dc_offset_enabled(dev[channel],
false, channel)))
{
warn(log, "Failed to disable FPGA DC offset on channel
%d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n", 0,
channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect maxsamples
(1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech
patchvonbraun@gmail.com wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with
latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link to
support that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936 Kbps,
16 * 19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use their
OFED drivers:(
On a related question. it seems that the streamer doesn't crash
anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no
conversion required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work as
far as I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format = "sc16",
.otw_format = "sc16",
.args = "",
.n_channels = 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL, LN, FN,
err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0], &maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d). %s.\n", 0,
FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0, FL, LN,
FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err = uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL, LN,
FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err = uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d). %s.\n", 0,
FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN, FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n", 0, FL,
LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN, FN,
channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0, &tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d). %s.\n",
0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate */
if (srate && !uhd_set_rx_rate_check(channel, srate)) return(FAIL);
/* Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain, channel, "")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db (%d). %s.\n",
0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel], channel, "", &tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n", 0, channel,
tmp,gain);
./* Set channel bw to conserve tuner resources. Not needed, set by
srate /
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./ Disable subtracting constant averaged background. Signal looks
cleaner */
if ((err = uhd_usrp_set_rx_dc_offset_enabled(dev[channel], false,
channel)))
{
warn(log, "Failed to disable FPGA DC offset on channel %d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n", 0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition
of zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
_______________________________________________
USRP-users mailing list --usrp-users@lists.ettus.com
To unsubscribe send an email tousrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is limited by MTU
size. Which is typically around 8000 or so for "jumbo frames".
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a send
frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the send_frame_size argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a receive
frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main Incorrect maxsamples
(364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link to support
that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936 Kbps, 16
- 19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use their OFED
drivers:(
On a related question. it seems that the streamer doesn't crash anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no conversion
required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work as far as I
can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format
= "sc16",
.otw_format
= "sc16",
.args = "",
.n_channels
= 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL, LN,
FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d). %s.\n",
0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0, FL,
LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err = uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL, LN,
FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err = uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d). %s.\n",
0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN, FN,
err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n", 0,
FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN, FN,
channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0, &tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d).
%s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate /
if (srate && !uhd_set_rx_rate_check(channel, srate)) return(FAIL);
/ Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain, channel, "")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db (%d).
%s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel], channel, "",
&tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n", 0,
channel, tmp, gain);
./* Set channel bw to conserve tuner resources. Not needed, set
by srate /
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./ Disable subtracting constant averaged background. Signal
looks cleaner */
if ((err = uhd_usrp_set_rx_dc_offset_enabled(dev[channel],
false, channel)))
{
warn(log, "Failed to disable FPGA DC offset on channel
%d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n", 0,
channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect maxsamples
(1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is limited by MTU size.
Which is typically around 8000 or so for "jumbo frames".
On 25/04/2025 23:33, Nikos Balkanas wrote:
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
Right, 9000, rather than 8000.
Upgrading to 10Gbit wont' give you larger MTU.
What you're trying to do, I think, is to solve a buffer-management
problem in your application at entirely the wrong
level in the stack.
It is EXCEEDINGLY COMMON for hardware drivers to only be able to deliver
in chunks that may not be perfectly adapted to
the requirements of your application. So, a common programming
pattern is to deal with this in your application.
You should probably look at example code like rx_samples_to_file
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a
send frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the send_frame_size argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a
receive frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition
of zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech
patchvonbraun@gmail.com wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the
Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with
latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link
to support that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936
Kbps, 16 * 19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use
their OFED drivers:(
On a related question. it seems that the streamer doesn't
crash anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no
conversion required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work
as far as I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format = "sc16",
.otw_format = "sc16",
.args = "",
.n_channels = 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d). %s.\n",
0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0,
FL, LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err =
uhd_rx_streamer_issue_stream_cmd(rx_streamer[0], &stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err =
uhd_set_thread_priority(uhd_default_thread_priority, true)))
warn(log, "Unable to set main thread priority (%d). %s.\n",
0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN,
FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n", 0,
FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN,
FN, channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0,
&tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d).
%s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate */
if (srate && !uhd_set_rx_rate_check(channel, srate))
return(FAIL);
/* Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain,
channel, "")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db (%d).
%s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel],
channel, "", &tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n", 0,
channel, tmp,gain);
./* Set channel bw to conserve tuner resources. Not needed, set
by srate */
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./* Disable subtracting constant averaged background. Signal
looks cleaner */
if ((err = uhd_usrp_set_rx_dc_offset_enabled(dev[channel], false,
channel)))
{
warn(log, "Failed to disable FPGA DC offset on channel %d(%d).
%s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n", 0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite
acquisition of zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
_______________________________________________
USRP-users mailing list --usrp-users@lists.ettus.com
To unsubscribe send an email tousrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is limited by MTU
size. Which is typically around 8000 or so for "jumbo frames".
Thanks for your time.
I will check out the example.
This is not a buffer problem. I just need 1024 Samples (real+imaginary) for
FFT...
I should be able to get them in a single pass.
You saw my code, not a smoking gun there.
This is probably is a physical problem.
Cable is an SFP fiber dedicated line. Cannot go bad.
Maybe the connections are not sitting right :(...
BR
Nikos
On Sat, Apr 26, 2025 at 6:45 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 23:33, Nikos Balkanas wrote:
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
Right, 9000, rather than 8000.
Upgrading to 10Gbit wont' give you larger MTU.
What you're trying to do, I think, is to solve a buffer-management problem
in your application at entirely the wrong
level in the stack.
It is EXCEEDINGLY COMMON for hardware drivers to only be able to deliver
in chunks that may not be perfectly adapted to
the requirements of your application. So, a common programming pattern
is to deal with this in your application.
You should probably look at example code like rx_samples_to_file
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a send
frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the send_frame_size argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a receive
frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main Incorrect maxsamples
(364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link to support
that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936 Kbps, 16
- 19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use their OFED
drivers:(
On a related question. it seems that the streamer doesn't crash anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no conversion
required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work as far as
I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format
= "sc16",
.otw_format
= "sc16",
.args = "",
.n_channels
= 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL, LN,
FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d). %s.\n",
0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0, FL,
LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err = uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err = uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d).
%s.\n", 0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN,
FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n", 0,
FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN, FN,
channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0, &tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d).
%s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate /
if (srate && !uhd_set_rx_rate_check(channel, srate)) return(FAIL);
/ Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain, channel, "")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db (%d).
%s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel], channel, "",
&tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n", 0,
channel, tmp, gain);
./* Set channel bw to conserve tuner resources. Not needed, set
by srate /
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./ Disable subtracting constant averaged background. Signal
looks cleaner */
if ((err = uhd_usrp_set_rx_dc_offset_enabled(dev[channel],
false, channel)))
{
warn(log, "Failed to disable FPGA DC offset on channel
%d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n",
0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is limited by MTU
size. Which is typically around 8000 or so for "jumbo frames".
Hi Marcus,
You were right. No need to change NIC:)
This is not a software issue. uhd_rx_streamer_max_num_samps runs right
after uhd initialization before
any other code had the chance to run.
Link capacity doesn't seem to be the issue either...
Running pchar on the link, descendant of pathchar, reports a throughput of
5.619 Kb/s requesting ICMP replies,
to varying packet sizes (32->9000 (MTU), incr by 32).
sudo pchar -m 9000 -p ipv4icmp usrp
https://www.kitchenlab.org/www/bmah/Software/pchar/
It corresponds to 351.218.019 16-bit samples or 175,609.044 32-bit samples,
if each sample is 32-bit(real + imag)
Seems that uhd is not running at link capacity but is doing smt else.
I will have to download and check with the sources...
The package version for Ubuntu 24.04 is uhd 4.6.0.
Where can I download the sources for uhd 4.6.0?
BR
Nikos
On Sat, Apr 26, 2025 at 7:02 AM Nikos Balkanas nbalkanas@gmail.com wrote:
Thanks for your time.
I will check out the example.
This is not a buffer problem. I just need 1024 Samples (real+imaginary)
for FFT...
I should be able to get them in a single pass.
You saw my code, not a smoking gun there.
This is probably is a physical problem.
Cable is an SFP fiber dedicated line. Cannot go bad.
Maybe the connections are not sitting right :(...
BR
Nikos
On Sat, Apr 26, 2025 at 6:45 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 23:33, Nikos Balkanas wrote:
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
Right, 9000, rather than 8000.
Upgrading to 10Gbit wont' give you larger MTU.
What you're trying to do, I think, is to solve a buffer-management
problem in your application at entirely the wrong
level in the stack.
It is EXCEEDINGLY COMMON for hardware drivers to only be able to deliver
in chunks that may not be perfectly adapted to
the requirements of your application. So, a common programming pattern
is to deal with this in your application.
You should probably look at example code like rx_samples_to_file
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a send
frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the send_frame_size argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a
receive frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link to support
that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936 Kbps,
16 * 19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use their
OFED drivers:(
On a related question. it seems that the streamer doesn't crash anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no conversion
required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work as far as
I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format = "sc16",
.otw_format = "sc16",
.args = "",
.n_channels = 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d). %s.\n",
0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0, FL,
LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err = uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err = uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d).
%s.\n", 0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN,
FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n", 0,
FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN,
FN, channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0,
&tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d).
%s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate /
if (srate && !uhd_set_rx_rate_check(channel, srate)) return(FAIL);
/ Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain, channel,
"")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db (%d).
%s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel], channel, "",
&tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n", 0,
channel, tmp, gain);
./* Set channel bw to conserve tuner resources. Not needed, set
by srate /
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./ Disable subtracting constant averaged background. Signal
looks cleaner */
if ((err = uhd_usrp_set_rx_dc_offset_enabled(dev[channel],
false, channel)))
{
warn(log, "Failed to disable FPGA DC offset on channel
%d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n",
0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is limited by MTU
size. Which is typically around 8000 or so for "jumbo frames".
On 27/04/2025 17:37, Nikos Balkanas wrote:
Hi Marcus,
You were right. No need to change NIC:)
This is not a software issue. uhd_rx_streamer_max_num_samps runs right
after uhd initialization before
any other code had the chance to run.
Link capacity doesn't seem to be the issue either...
Running pchar on the link, descendant of pathchar, reports a
throughput of 5.619 Kb/s requesting ICMP replies,
to varying packet sizes (32->9000 (MTU), incr by 32).
sudo pchar -m 9000 -p ipv4icmp usrp
https://www.kitchenlab.org/www/bmah/Software/pchar/
It corresponds to 351.218.019 16-bit samples or 175,609.044 32-bit
samples, if each sample is 32-bit(real + imag)
Seems that uhd is not running at link capacity but is doing smt else.
I will have to download and check with the sources...
The package version for Ubuntu 24.04 is uhd 4.6.0.
Where can I download the sources for uhd 4.6.0?
BR
Nikos
YOu CANNOT use ICMP tests to determine link capacity with a USRP -- ICMP
is processed via completely different
"stack" in the radio.
Use "benchmark_rate" instead.
On Sat, Apr 26, 2025 at 7:02 AM Nikos Balkanas nbalkanas@gmail.com
wrote:
Thanks for your time.
I will check out the example.
This is not a buffer problem. I just need 1024 Samples
(real+imaginary) for FFT...
I should be able to get them in a single pass.
You saw my code, not a smoking gun there.
This is probably is a physical problem.
Cable is an SFP fiber dedicated line. Cannot go bad.
Maybe the connections are not sitting right :(...
BR
Nikos
On Sat, Apr 26, 2025 at 6:45 AM Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 25/04/2025 23:33, Nikos Balkanas wrote:
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
Right, 9000, rather than 8000.
Upgrading to 10Gbit wont' give you larger MTU.
What you're trying to do, I think, is to solve a
buffer-management problem in your *application* at entirely
the wrong
level in the stack.
It is EXCEEDINGLY COMMON for hardware drivers to only be able
to deliver in chunks that may not be perfectly adapted to
the requirements of your application. So, a common
programming pattern is to deal with this in your application.
You should probably look at example code like rx_samples_to_file
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD
recommends a send frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This
may negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the send_frame_size
argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD
recommends a receive frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This
may negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size
argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized
sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
[WARNING] [UDP] The send buffer could not be resized
sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main
Incorrect maxsamples (364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite
acquisition of zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the
Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to
work with latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a
10Gbit link to support that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996
= 31.936 Kbps, 16 * 19960 = 319.360 Kbps well short of a
10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old
to use their OFED drivers:(
On a related question. it seems that the streamer
doesn't crash anymore
when receiving less than MAXSPS samples, instead it
reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16,
otw=sc16, so no conversion required.
Streamer still doesn't read anything. Is there a
reason for it?
You'd need to share more of your code. This should
just work as far as I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format = "sc16",
.otw_format = "sc16",
.args = "",
.n_channels = 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode =
UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0],
&stream_args, rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n",
0, FL, LN, FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err =
uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0]
(%d). %s.\n", 0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected
%d.\n", 0, FL, LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err =
uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d).
%s.\n", 0, FL, LN, FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err =
uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d).
%s.\n", 0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0,
FL, LN, FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d).
%s.\n", 0, FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0,
FL, LN, FN, channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err =
uhd_usrp_get_master_clock_rate(dev[channel], 0, &tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz
(%d). %s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0,
tmp/1000000);
/* Set the sample rate */
if (srate && !uhd_set_rx_rate_check(channel, srate))
return(FAIL);
/* Set the tuner gain SBX-120 is 0-31.5 in .5 db
steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel],
gain, channel, "")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db
(%d). %s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err =
uhd_usrp_get_rx_gain(dev[channel], channel, "", &tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf)
dB\n", 0, channel, tmp,gain);
./* Set channel bw to conserve tuner resources. Not
needed, set by srate */
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./* Disable subtracting constant averaged background.
Signal looks cleaner */
if ((err =
uhd_usrp_set_rx_dc_offset_enabled(dev[channel], false,
channel)))
{
warn(log, "Failed to disable FPGA DC offset on channel
%d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n",
0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0;
Boost_108300; UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to
30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main
Incorrect maxsamples (1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]:
1996
[WARNING] [0/Radio#0] Ignoring stream command for finite
acquisition of zero samples
I hope this reads OK. Maybe next time I should attach
the code:)
TIA
Nikos
_______________________________________________
USRP-users mailing list --usrp-users@lists.ettus.com
To unsubscribe send an email tousrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is
limited by MTU size. Which is typically around 8000 or
so for "jumbo frames".
For that i will need the sources.
Do you know where can I download the UHD 4.6.0 sources?
TIA
Nikos
On Mon, Apr 28, 2025 at 12:39 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 27/04/2025 17:37, Nikos Balkanas wrote:
Hi Marcus,
You were right. No need to change NIC:)
This is not a software issue. uhd_rx_streamer_max_num_samps runs right
after uhd initialization before
any other code had the chance to run.
Link capacity doesn't seem to be the issue either...
Running pchar on the link, descendant of pathchar, reports a throughput of
5.619 Kb/s requesting ICMP replies,
to varying packet sizes (32->9000 (MTU), incr by 32).
sudo pchar -m 9000 -p ipv4icmp usrp
https://www.kitchenlab.org/www/bmah/Software/pchar/
It corresponds to 351.218.019 16-bit samples or 175,609.044 32-bit
samples, if each sample is 32-bit(real + imag)
Seems that uhd is not running at link capacity but is doing smt else.
I will have to download and check with the sources...
The package version for Ubuntu 24.04 is uhd 4.6.0.
Where can I download the sources for uhd 4.6.0?
BR
Nikos
YOu CANNOT use ICMP tests to determine link capacity with a USRP -- ICMP
is processed via completely different
"stack" in the radio.
Use "benchmark_rate" instead.
On Sat, Apr 26, 2025 at 7:02 AM Nikos Balkanas nbalkanas@gmail.com
wrote:
Thanks for your time.
I will check out the example.
This is not a buffer problem. I just need 1024 Samples (real+imaginary)
for FFT...
I should be able to get them in a single pass.
You saw my code, not a smoking gun there.
This is probably is a physical problem.
Cable is an SFP fiber dedicated line. Cannot go bad.
Maybe the connections are not sitting right :(...
BR
Nikos
On Sat, Apr 26, 2025 at 6:45 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 23:33, Nikos Balkanas wrote:
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
Right, 9000, rather than 8000.
Upgrading to 10Gbit wont' give you larger MTU.
What you're trying to do, I think, is to solve a buffer-management
problem in your application at entirely the wrong
level in the stack.
It is EXCEEDINGLY COMMON for hardware drivers to only be able to deliver
in chunks that may not be perfectly adapted to
the requirements of your application. So, a common programming
pattern is to deal with this in your application.
You should probably look at example code like rx_samples_to_file
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a send
frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the send_frame_size argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a
receive frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech <
patchvonbraun@gmail.com> wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link to
support that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936 Kbps,
16 * 19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use their
OFED drivers:(
On a related question. it seems that the streamer doesn't crash anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no conversion
required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work as far
as I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format = "sc16",
.otw_format = "sc16",
.args =
"",
.n_channels = 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d).
%s.\n", 0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0,
FL, LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err = uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err = uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d).
%s.\n", 0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN,
FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n", 0,
FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN,
FN, channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0,
&tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d).
%s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate /
if (srate && !uhd_set_rx_rate_check(channel, srate))
return(FAIL);
/ Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain, channel,
"")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db
(%d). %s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel], channel, "",
&tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n",
0, channel, tmp, gain);
./* Set channel bw to conserve tuner resources. Not needed,
set by srate /
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./ Disable subtracting constant averaged background. Signal
looks cleaner */
if ((err = uhd_usrp_set_rx_dc_offset_enabled(dev[channel],
false, channel)))
{
warn(log, "Failed to disable FPGA DC offset on
channel %d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel %d\n",
0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is limited by MTU
size. Which is typically around 8000 or so for "jumbo frames".
On 27/04/2025 19:34, Nikos Balkanas wrote:
For that i will need the sources.
Do you know where can I download the UHD 4.6.0 sources?
TIA
Nikos
If you have an installed version of UHD on your system, then the
examples should also have been installed. How did you install
UHD?
You might need to install "uhd-host" if you installed from packaged
binaries, but all the examples and utilities should be
there along with the libraries.
But the GIT repo for the UHD source is here:
https://github.com/EttusResearch/uhd
These days, most distros package UHD, so in many cases you don't need to
build from source.
On Mon, Apr 28, 2025 at 12:39 AM Marcus D. Leech
patchvonbraun@gmail.com wrote:
On 27/04/2025 17:37, Nikos Balkanas wrote:
Hi Marcus,
You were right. No need to change NIC:)
This is not a software issue. uhd_rx_streamer_max_num_samps runs
right after uhd initialization before
any other code had the chance to run.
Link capacity doesn't seem to be the issue either...
Running pchar on the link, descendant of pathchar, reports a
throughput of 5.619 Kb/s requesting ICMP replies,
to varying packet sizes (32->9000 (MTU), incr by 32).
sudo pchar -m 9000 -p ipv4icmp usrp
https://www.kitchenlab.org/www/bmah/Software/pchar/
It corresponds to 351.218.019 16-bit samples or 175,609.044
32-bit samples, if each sample is 32-bit(real + imag)
Seems that uhd is not running at link capacity but is doing smt else.
I will have to download and check with the sources...
The package version for Ubuntu 24.04 is uhd 4.6.0.
Where can I download the sources for uhd 4.6.0?
BR
Nikos
YOu CANNOT use ICMP tests to determine link capacity with a USRP
-- ICMP is processed via completely different
"stack" in the radio.
Use "benchmark_rate" instead.
On Sat, Apr 26, 2025 at 7:02 AM Nikos Balkanas
<nbalkanas@gmail.com> wrote:
Thanks for your time.
I will check out the example.
This is not a buffer problem. I just need 1024 Samples
(real+imaginary) for FFT...
I should be able to get them in a single pass.
You saw my code, not a smoking gun there.
This is probably is a physical problem.
Cable is an SFP fiber dedicated line. Cannot go bad.
Maybe the connections are not sitting right :(...
BR
Nikos
On Sat, Apr 26, 2025 at 6:45 AM Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 25/04/2025 23:33, Nikos Balkanas wrote:
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
Right, 9000, rather than 8000.
Upgrading to 10Gbit wont' give you larger MTU.
What you're trying to do, I think, is to solve a
buffer-management problem in your *application* at
entirely the wrong
level in the stack.
It is EXCEEDINGLY COMMON for hardware drivers to only be
able to deliver in chunks that may not be perfectly
adapted to
the requirements of your application. So, a common
programming pattern is to deal with this in your application.
You should probably look at example code like
rx_samples_to_file
[INFO] [UHD] linux; GNU C++ version 13.2.0;
Boost_108300; UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD
recommends a send frame size of at least 8000 for best
performance, but your configuration will only allow
1472.This may negatively impact your maximum achievable
sample rate.
Check the MTU on the interface and/or the
send_frame_size argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD
recommends a receive frame size of at least 8000 for best
performance, but your configuration will only allow
1472.This may negatively impact your maximum achievable
sample rate.
Check the MTU on the interface and/or the
recv_frame_size argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized
sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to
30 (30) dB
[WARNING] [UDP] The send buffer could not be resized
sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main
Incorrect maxsamples (364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite
acquisition of zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs,
before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more)
to work with latest uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a
10Gbit link to support that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 *
1996 = 31.936 Kbps, 16 * 19960 = 319.360 Kbps well
short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too
old to use their OFED drivers:(
On a related question. it seems that the
streamer doesn't crash anymore
when receiving less than MAXSPS samples,
instead it reads 0:(
This was due to the sse2 code not aligned in
convert.
I change my stream args to cpu_format=sc16,
otw=sc16, so no conversion required.
Streamer still doesn't read anything. Is there
a reason for it?
You'd need to share more of your code. This
should just work as far as I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format = "sc16",
.otw_format = "sc16",
.args = "",
.n_channels = 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0],
&stream_args, rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d).
%s.\n", 0, FL, LN, FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err =
uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0]
(%d). %s.\n", 0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected
%d.\n", 0, FL, LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0,
maxsamps);
if ((err =
uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d).
%s.\n", 0, FL, LN, FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate,
double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err =
uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority
(%d). %s.\n", 0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel],
"type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n",
0, FL, LN, FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err =
uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d]
(%d). %s.\n", 0, FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d).
%s.\n", 0, FL, LN, FN, channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err =
uhd_usrp_get_master_clock_rate(dev[channel], 0,
&tmp)))
{
error(log, "Failed to set master clock to %.0lf
Mhz (%d). %s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n",
0, tmp/1000000);
/* Set the sample rate */
if (srate && !uhd_set_rx_rate_check(channel,
srate)) return(FAIL);
/* Set the tuner gain SBX-120 is 0-31.5 in .5
db steps */
if ((err =
uhd_usrp_set_rx_gain(dev[channel], gain,
channel, "")))
{
error(log, "Failed to set tuner[%d] gain to
%.0lf db (%d). %s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err =
uhd_usrp_get_rx_gain(dev[channel], channel, "",
&tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf)
dB\n", 0, channel, tmp,gain);
./* Set channel bw to conserve tuner resources. Not
needed, set by srate */
uhd_usrp_set_rx_bandwidth(dev[channel], srate,
channel);
./* Disable subtracting constant averaged
background. Signal looks cleaner */
if ((err =
uhd_usrp_set_rx_dc_offset_enabled(dev[channel],
false, channel)))
{
warn(log, "Failed to disable FPGA DC offset on
channel %d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel
%d\n", 0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0;
Boost_108300; UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with
args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is
at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set
to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*]
scanner.l:1446:main Incorrect maxsamples (1996).
Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max
samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for
finite acquisition of zero samples
I hope this reads OK. Maybe next time I should
attach the code:)
TIA
Nikos
_______________________________________________
USRP-users mailing list --usrp-users@lists.ettus.com
To unsubscribe send an email tousrp-users-leave@lists.ettus.com
I believe that max number of samples-per-buffer is
limited by MTU size. Which is typically around
8000 or so for "jumbo frames".
Ubuntu packages...
No -dev, => no includes:(
The ICMP test is fine for testing physical wear (line, connectors OSI layer
2)
Ofc a dedicated usrp benchmark is better for application (layer 4)
benchmark:)
PS. If this conversation is getting long, we can switch to private mail...
On Mon, Apr 28, 2025 at 2:45 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 27/04/2025 19:34, Nikos Balkanas wrote:
For that i will need the sources.
Do you know where can I download the UHD 4.6.0 sources?
TIA
Nikos
If you have an installed version of UHD on your system, then the examples
should also have been installed. How did you install
UHD?
You might need to install "uhd-host" if you installed from packaged
binaries, but all the examples and utilities should be
there along with the libraries.
But the GIT repo for the UHD source is here:
https://github.com/EttusResearch/uhd
These days, most distros package UHD, so in many cases you don't need to
build from source.
On Mon, Apr 28, 2025 at 12:39 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 27/04/2025 17:37, Nikos Balkanas wrote:
Hi Marcus,
You were right. No need to change NIC:)
This is not a software issue. uhd_rx_streamer_max_num_samps runs right
after uhd initialization before
any other code had the chance to run.
Link capacity doesn't seem to be the issue either...
Running pchar on the link, descendant of pathchar, reports a throughput
of 5.619 Kb/s requesting ICMP replies,
to varying packet sizes (32->9000 (MTU), incr by 32).
sudo pchar -m 9000 -p ipv4icmp usrp
https://www.kitchenlab.org/www/bmah/Software/pchar/
It corresponds to 351.218.019 16-bit samples or 175,609.044 32-bit
samples, if each sample is 32-bit(real + imag)
Seems that uhd is not running at link capacity but is doing smt else.
I will have to download and check with the sources...
The package version for Ubuntu 24.04 is uhd 4.6.0.
Where can I download the sources for uhd 4.6.0?
BR
Nikos
YOu CANNOT use ICMP tests to determine link capacity with a USRP -- ICMP
is processed via completely different
"stack" in the radio.
Use "benchmark_rate" instead.
On Sat, Apr 26, 2025 at 7:02 AM Nikos Balkanas nbalkanas@gmail.com
wrote:
Thanks for your time.
I will check out the example.
This is not a buffer problem. I just need 1024 Samples (real+imaginary)
for FFT...
I should be able to get them in a single pass.
You saw my code, not a smoking gun there.
This is probably is a physical problem.
Cable is an SFP fiber dedicated line. Cannot go bad.
Maybe the connections are not sitting right :(...
BR
Nikos
On Sat, Apr 26, 2025 at 6:45 AM Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 25/04/2025 23:33, Nikos Balkanas wrote:
Actually MTU is 9000. This is one of the recommendations...
I tried it with MTU 1500. It was worse:(
maxsamples dropped to 364...
Right, 9000, rather than 8000.
Upgrading to 10Gbit wont' give you larger MTU.
What you're trying to do, I think, is to solve a buffer-management
problem in your application at entirely the wrong
level in the stack.
It is EXCEEDINGLY COMMON for hardware drivers to only be able to
deliver in chunks that may not be perfectly adapted to
the requirements of your application. So, a common programming
pattern is to deal with this in your application.
You should probably look at example code like rx_samples_to_file
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 1472 bytes.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a send
frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the send_frame_size argument.
[WARNING] [X300] For the 192.168.40.2 connection, UHD recommends a
receive frame size of at least 8000 for best
performance, but your configuration will only allow 1472.This may
negatively impact your maximum achievable sample rate.
Check the MTU on the interface and/or the recv_frame_size argument.
[INFO] [GPS] No GPSDO found
[INFO] [X300] Radio 1x clock: 200 MHz
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [+] Created USRP with args
Sat Apr 26 06:30:34 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 06:30:34 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
[WARNING] [UDP] The send buffer could not be resized sufficiently.
Target sock buff size: 24912805 bytes.
Actual sock buff size: 1048576 bytes.
See the transport application notes on buffer resizing.
Please run: sudo sysctl -w net.core.wmem_max=24912805
Sat Apr 26 06:30:34 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (364). Expected 19960.
Sat Apr 26 06:30:34 2025 [00] [+] Max samples/buffer[0]: 364
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition of
zero sam
Nikos
On Sat, Apr 26, 2025 at 5:46 AM Marcus D. Leech <
patchvonbraun@gmail.com> wrote:
On 25/04/2025 22:26, Nikos Balkanas wrote:
Thanks Marcus,
for your fast reply.
On Sat, Apr 26, 2025 at 4:08 AM Marcus D. Leech <
patchvonbraun@gmail.com> wrote:
On 25/04/2025 20:50, Nikos Balkanas wrote:
Hello,
I need to buy a new NIC. What would you suggest?
The one I use is an old Mellanox 10 Gbs, before the Connect-4 series.
It can only do 1996 S/s, need 19960 (10x more) to work with latest
uhd.
Using Ubuntu 24.04 and uhd 4.6.0
So, 1.996ksps vs 19.960ksps? You hardly need a 10Gbit link to
support that. So, perhaps something
is being lost here in your requirements?
True. Can't explain it in terms of bandwidth. 16 * 1996 = 31.936 Kbps,
16 * 19960 = 319.360 Kbps well short of a 10 Gbps line:(
Does a complex pair count as 1 sample, or 2?
I have followed all the instructions in
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks,
Even installed the DPDK drivers. My Mellanox is too old to use their
OFED drivers:(
On a related question. it seems that the streamer doesn't crash
anymore
when receiving less than MAXSPS samples, instead it reads 0:(
This was due to the sse2 code not aligned in convert.
I change my stream args to cpu_format=sc16, otw=sc16, so no
conversion required.
Streamer still doesn't read anything. Is there a reason for it?
You'd need to share more of your code. This should just work as far
as I can tell.
Thanks. these are just the usrp code:
int main()
{
uhd_stream_args_t stream_args =
{
.cpu_format = "sc16",
.otw_format = "sc16",
.args =
"",
.n_channels = 1,
.channel_list = &channel
};
..uhd_stream_cmd_t stream_cmd =
{
.stream_mode = UHD_STREAM_MODE_NUM_SAMPS_AND_DONE,
.stream_now = true
};
if (uhd_init(0, 0, gain)) do_exit(20);
if ((err = uhd_usrp_get_rx_stream(dev[0], &stream_args,
rx_streamer[0])))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
uhd_rx_streamer_free(&rx_streamer[0]);
rx_streamer[0] = NULL;
uhd_rx_metadata_free(&md[0]);
md[0] = NULL;
do_exit(30);
}
if ((err = uhd_rx_streamer_max_num_samps(rx_streamer[0],
&maxsamps)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to get max samples/buffer[0] (%d).
%s.\n", 0, FL, LN, FN, err,
..errmsg);
do_exit(35);
}
if (maxsamps != MAXSMPS)
warn(log, "Incorrect maxsamples (%ld). Expected %d.\n", 0,
FL, LN, FN, maxsamps,
MAXSMPS);
info(log, "Max samples/buffer[0]: %ld\n", 0, maxsamps);
if ((err = uhd_rx_streamer_issue_stream_cmd(rx_streamer[0],
&stream_cmd)))
{
uhd_get_last_error(errmsg, 127);
error(log, "Failed to start streamer[0] (%d). %s.\n", 0, FL,
LN, FN, err, errmsg);
do_exit(40);
}
[...]
do_exit(0)
}
bool uhd_init(size_t channel, double srate, double gain)
{
double tmp;
uhd_rx_metadata_error_code_t err;
if ((err = uhd_set_thread_priority(uhd_default_thread_priority,
true)))
warn(log, "Unable to set main thread priority (%d).
%s.\n", 0, FL, LN, FN,
err, uhdError(err));
/* Create USRP */
f ((err = uhd_usrp_make(&dev[channel], "type=x300")))
{
error(log, "Failed to create USRP (%d). %s.\n", 0, FL, LN,
FN, err,
uhdError(err));
dev[channel] = NULL;
return(FAIL);
}
info(stderr, "Created USRP with args\n", 0);
/* Create RX streamer */
if ((err = uhd_rx_streamer_make(&rx_streamer[channel])))
{
error(log, "Failed to create rx_streamer[%d] (%d). %s.\n",
0, FL, LN, FN,
channel, err, uhdError(err));
return(FAIL);
}
/* Create RX metadata */
if ((err = uhd_rx_metadata_make(&md[channel])))
{
error(log, "Failed to create md[%d] (%d). %s.\n", 0, FL, LN,
FN, channel,
err, uhdError(err));
return(FAIL);
}
/* Get master clock rate */
if ((err = uhd_usrp_get_master_clock_rate(dev[channel], 0,
&tmp)))
{
error(log, "Failed to set master clock to %.0lf Mhz (%d).
%s.\n", 0, FL,
LN, FN, tmp/1000000, err, uhdError(err));
return(FAIL);
}
info(stderr, "Master clock is at %.0lf Mhz\n", 0, tmp/1000000);
/* Set the sample rate /
if (srate && !uhd_set_rx_rate_check(channel, srate))
return(FAIL);
/ Set the tuner gain SBX-120 is 0-31.5 in .5 db steps */
if ((err = uhd_usrp_set_rx_gain(dev[channel], gain, channel,
"")))
{
error(log, "Failed to set tuner[%d] gain to %.0lf db
(%d). %s.\n", 0, FL,
LN, FN, channel, gain, err, uhdError(err));
return(FAIL);
}
if (!(err = uhd_usrp_get_rx_gain(dev[channel], channel, "",
&tmp)))
info(log, "Tuner[%d] gain set to %.0lf (%.0lf) dB\n",
0, channel, tmp, gain);
./* Set channel bw to conserve tuner resources. Not needed,
set by srate /
uhd_usrp_set_rx_bandwidth(dev[channel], srate, channel);
./ Disable subtracting constant averaged background. Signal
looks cleaner */
if ((err =
uhd_usrp_set_rx_dc_offset_enabled(dev[channel], false, channel)))
{
warn(log, "Failed to disable FPGA DC offset on
channel %d(%d). %s.\n", 0,
FL, LN, FN, channel, err, uhdError(err));
}
info(stderr, "Disabled FPGA DC offset on channel
%d\n", 0, channel);
return(SUCCESS);
}
This is the generated output:
[INFO] [UHD] linux; GNU C++ version 13.2.0; Boost_108300;
UHD_4.6.0.0+ds1-5.1ubuntu0.24.04.1
[INFO] [X300] X300 initialization sequence...
[INFO] [X300] Maximum frame size: 8000 bytes.
[INFO] [X300] Radio 1x clock: 200 MHz
Sat Apr 26 03:33:48 2025 [00] [+] Created USRP with args
Sat Apr 26 03:33:48 2025 [00] [+] Master clock is at 200 Mhz
Sat Apr 26 03:33:48 2025 [00] [+] Tuner[0] gain set to 30 (30) dB
Sat Apr 26 03:33:48 2025 [00] [*] scanner.l:1446:main Incorrect
maxsamples (1996). Expected 19960.
Sat Apr 26 03:33:48 2025 [00] [+] Max samples/buffer[0]: 1996
[WARNING] [0/Radio#0] Ignoring stream command for finite acquisition
of zero samples
I hope this reads OK. Maybe next time I should attach the code:)
TIA
Nikos
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I believe that max number of samples-per-buffer is limited by MTU
size. Which is typically around 8000 or so for "jumbo frames".