On Wed, Feb 23, 2022 at 2:04 PM Brian Padalino <bpadal...@gmail.com> wrote:
> On Wed, Feb 23, 2022 at 1:03 PM Marcus D. Leech <patchvonbr...@gmail.com> > wrote: > >> On 2022-02-23 12:00, zlika_...@hotmail.com wrote: >> > >> > Thanks for your answer. >> > >> > I tried to use benchmark_rate, and I don’t have any sample loss at >> > 200MS/s. >> > >> > On GnuRadio with a very simple flowgraph (USRP Source -> Null Sink) I >> > still have very regular (every few seconds) overflows. >> > >> > In both cases, the CPU load of each core never goes over ~25%. >> > >> > Is there any particular performance tips to know on GnuRadio (e.g. >> > playing with the min/max output buffer sizes of the blocks) to >> > optimize the throughput? >> > >> > >> A Gnu Radio flow-graph will *NEVER* be as performant, for "simple >> things" as a hand-coded equivalent, because it has extra overhead in >> managing buffers and threads >> and so-on. >> > > While this may be true in general, the test case is said to be (USRP > Source -> Null Sink). This is the most trivial case and should basically > be the exact same as what benchmark_rate is running, and yet GNU Radio has > overflow whereas benchmark_rate does not. When I was testing this, another > interesting thing happened where once an overflow occurred in GNU Radio, it > never recovered and it was O all the time and with a very low/strange > sample rate coming in - as if something was stalled in the pipeline on the > radio and repeatedly thrashing some state. That is, until I ran > benchmark_rate. Once benchmark_rate was able to run properly, GNU Radio > was able to run fine until the next O. This is with GNU Radio maint-3.10 > and whatever is built in with gr-uhd linked against UHD 4.10.5 I believe. > > In my opinion, something fishy is happening in GNU Radio with the X310 > that is not exhibited when using benchmark_rate. > My colleague has opened a ticket with GNU Radio to follow this issue: https://github.com/gnuradio/gnuradio/issues/5602 Brian >
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