Compiled uhd 4.6.0 in debug mode. >From the output I get: [DEBUG] [0/Radio#0] spp(= samples per package) value 2032 exceeds MTU of 8000! Coercing to 1996 Mon Apr 28 09:57:02 2025 [00] [*] scanner.l:1443:main Incorrect maxsamples (1996). Expected 19960. Mon Apr 28 09:57:02 2025 [00] [+] Max samples/buffer[0]: 1996 1) Line mtu is 9000 not 8000 2) 2032 is not larger than 8000 <= Bug? 3) seems that spp is setting my maxsmps
Of the examples I tried the rx_samples_c. It is the same case like mine: single usrp. We use the same commands and we are getting the same output:( 1996 maxsmpls. The error text and code are from host/lib/rfnoc/radio_control_impl.cpp: 199 I would rather not touch it. I don't know the uhd architecture and especially the rfnoc/uhd interface. Besides I am a c programmer, not c++:( multi_usrp class has a set_rx_spp function, but it is not for me:( HTH Nikos On Mon, Apr 28, 2025 at 6:02 AM Nikos Balkanas <nbalka...@gmail.com> wrote: > Point taken:) I'm proposing smt different: > pchar +ICMP are just to test line and connectors. First step. Not to bench > USRP. > benchmark_rate is to bench/stress usrp. > These 2 are independent, and complementary. > Pchar is telling me nothing more than my fiber cable and connectors are > good. > It saved me a trip tomorrow to my local PC store, where fiber cable and > connectors are ~7 E each. > benchmark_rate on the other hand is quite interesting. > It points to software,and particularly my uhd_init() > > Just found and downloaded the sources to uhd 4.6.0 from Ubuntu Launchpad. > Now I can go through the source of the example you told me:) > Ettus used to keep an archive of old uhd sources around. Seems it's > gone:( > Open source means, among others, free to choose the source version that > you need... > Having the latest source in Github is only partly open source. > During development we need to freeze updates. When in 5 years we go > into production we can't find the old sources anymore:( > If a customer discovers a bug, not in our code, but in one of the > libraries that > we use, what are we gonna do? > > BR > Nikos > > > > On Mon, Apr 28, 2025 at 5:01 AM Marcus D. Leech <patchvonbr...@gmail.com> > wrote: > >> On 27/04/2025 21:58, Nikos Balkanas wrote: >> >> My bad: >> >> throughput of 5.619 Kb/s requesting ICMP replies, +> throughput of 5,619 >> Kb/s requesting ICMP replies >> Local thousand separator is ".", whereas in the US is ",":( >> >> It is STILL the case that the ICMP machinery in these radios is >> ABSOLUTELY NOT on the fast-path inside >> the hardware. The only way to get a good feel for how much sample >> bandwidth they can process is >> with examples like "benchmark_rate". >> >> >> >> On Mon, Apr 28, 2025 at 12:37 AM Nikos Balkanas <nbalka...@gmail.com> >> 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 >>> >>> On Sat, Apr 26, 2025 at 7:02 AM Nikos Balkanas <nbalka...@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 < >>>> patchvonbr...@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 < >>>>> patchvonbr...@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 < >>>>>> patchvonbr...@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-le...@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". >>>>>> >>>>>> >>>>>> >>>>> >>
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