Messages in this thread |  | | Date | Sun, 9 Oct 2016 15:41:42 +0800 | From | Aaron Lu <> | Subject | Re: [LKP] [lkp] [sctp] a6c2f79287: netperf.Throughput_Mbps -37.2% regression |
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On Mon, Oct 03, 2016 at 10:32:04AM +0800, Xin Long wrote: > On Fri, Sep 30, 2016 at 3:05 PM, Aaron Lu <aaron.lu@intel.com> wrote: > > On 08/23/2016 05:44 AM, Marcelo Ricardo Leitner wrote: > >> Em 19-08-2016 04:24, Aaron Lu escreveu: > >>> On Fri, Aug 19, 2016 at 04:19:39AM -0300, Marcelo Ricardo Leitner wrote: > >>>> Hi, > >>>> > >>>> Em 19-08-2016 02:29, Aaron Lu escreveu: > >>>> ... > >>>>> It doesn't look insane and sctp_wait_for_sndbuf may actually have > >>>>> something to do with a larger sctp_chunk I suppose? > >>>>> > >>>>> The same perf record doesn't capture any sample for the good commit, > >>>>> which suggests the nerperf process doesn't sleep in sctp_wait_for_sndbuf. > >>>> > >>>> Ahhh yes! It does, and then it would mean your txbuf is too small for the > >>>> chunk sizes you're using (sctp tests option -m). > >>>> > >>>> What's your netperf cmdline again please? > >>> > >>> netperf -4 -t SCTP_STREAM_MANY -c -C -l 300 -- -m 10K -H 127.0.0.1 > >>> > >>> Is the 10K used here a problem? If so, can you suggest a proper value > >>> for our netperf performance test? Thanks. > >> > >> We're still working on this. Xin could reproduce it on an i3 too, but > >> I'm afraid this commit just unmasked an issue in there. You're > >> overloading the CPU by too much when spawning 8 parallel netperf's on a > >> 4-core system, seems that commit a6c2f79287 was that last rock that made > >> it slip into a precipice. sctp's cwnd and rwnd management are not as > >> good as tcp's and now it seems you're triggering a corner case. > >> > >> I hope to have more soon. > > > > I wonder if there is any update on this issue? > > > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > be4947b sctp: change to check peer prsctp_capable when using prsctp polices > 0605483 sctp: remove prsctp_param from sctp_chunk > 73dca12 sctp: move sent_count to the memory hole in sctp_chunk > > These three commit can avoid this issue by recovering sctp_chunk size.
Thanks for the update, I just confirmed the throughput is back on my desktop.
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