Hi Andrew, I see what you mean regarding the documentation comment about one streamer only. But, this doesn't make sense to me. I wonder if the documentation is in error. I always use multiple rx and tx streamers. However, I don't often destroy and recreate them on the fly. Anyway, it was my understanding that the true restriction is that you can only have one rx_streamer (or tx_streamer) for a given channel when using a multi_usrp object. So, if you have a 4 channel device you should be able to have one rx_streamer using channels 0,1 and another using channels 2,3. Rob
On Wed, Aug 23, 2023 at 10:17 AM Andrew Fountain via USRP-users < usrp-users@lists.ettus.com> wrote: > Hey Brian, > > Thanks for the input. Yeah making the rx_streamers at the beginning and > keeping them around resolves the issue in that test program -- no > segfaults after 10000 Rx iterations total from the two threads. Makes > sense; if the issue is happening in rx_streamer creation, then we should do > that as little as possible. We'd just have to re-create the streamers when > we re-tune or some such. > > I was perusing the docs and it also seems like there is also a more > fundamental misunderstanding on my end. It looks like there can always only > be one RX streamer at a time per multi_usrp object as per this little note > in the docs: > https://files.ettus.com/manual/classuhd_1_1device.html#a0a9e36f353dcce36b4dd8d394c8813e3 > unless > I misunderstand. Curses! That seems to indicate that I am relying on > undefined behavior in either case, even though everything seems to now work > as expected. > Ideally the UHD would have complained that I was doing that! Ah well. > > Time to re-architecture some stuff! 🙂 > > Thank you, > Andrew Fountain > Black River Systems Co., Inc. > 162 Genesee Street > Utica, NY 13502 > > > ------------------------------ > *From:* Brian Padalino <bpadal...@gmail.com> > *Sent:* Tuesday, August 22, 2023 4:22 PM > *To:* Andrew Fountain <afount...@brsc.com> > *Cc:* usrp-users@lists.ettus.com <usrp-users@lists.ettus.com> > *Subject:* Re: [USRP-users] Re: UHD4 segmentation fault on creating > rx_streamer > > You don't often get email from bpadal...@gmail.com. Learn why this is > important <https://aka.ms/LearnAboutSenderIdentification> > On Tue, Aug 22, 2023 at 4:16 PM Andrew Fountain via USRP-users < > usrp-users@lists.ettus.com> wrote: > > Here is the output of that program with a debug build of UHD v4.4.0.0 . It > seems to point out this line > https://github.com/EttusResearch/uhd/blob/UHD-4.4/host/lib/rfnoc/rfnoc_graph.cpp#L393 > <https://usg02.safelinks.protection.office365.us/?url=https%3A%2F%2Fgithub.com%2FEttusResearch%2Fuhd%2Fblob%2FUHD-4.4%2Fhost%2Flib%2Frfnoc%2Frfnoc_graph.cpp%23L393&data=05%7C01%7Cafountain%40brsc.com%7C080e13d2bdc743f6fddd08dba34d96b2%7C5ed13283606a46b1bd4f758a462df882%7C1%7C0%7C638283325860702606%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=DgXydmUT8Sx3Ut50BrPNkaBRYTbXTYO2O80zpAu%2F%2Fy4%3D&reserved=0> > > It doesn't seem to be some weird threading issue related to getting > multiple rx_streamers at the same time; adding a lock around that access to > that get_rx_stream function still yields segmentation faults at the same > point in get_rx_stream. > > > Are you sure? > > Can you move the streamer creation to be outside of the for loop and just > iterate on the stream args, issue command, and recv()? > > Brian > _______________________________________________ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com >
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