Date: Fri, 11 Sep 2015 12:46:25 +0300 From: Dmitry Sivachenko <trtrmitya@gmail.com> To: FreeBSD Net <freebsd-net@freebsd.org>, hiren@strugglingcoder.info Subject: Re: netisr process eats 100% cpu Message-ID: <EA9AD61B-E709-4387-8D5E-A33E25475D81@gmail.com> In-Reply-To: <C4039E45-3DC7-4E1A-9E46-853FE812B906@gmail.com> References: <C4039E45-3DC7-4E1A-9E46-853FE812B906@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> hiren panchasara <hiren at strugglingcoder.info> wrote: >=20 > Unsure at the moment if loopback is causing the trouble for you or = not. > See: (please keep me CC'ed, I am not subscribed to -net) > > = https://lists.freebsd.org/pipermail/freebsd-net/2015-February/041239.html > > Yes, this thread looks similar. > You may want to try: > 1) pmcstat and see if you can catch something What particular should I look for? Here is first lines of pmcstat -T -S = instructions -w 1: PMC: [INSTR_RETIRED_ANY] Samples: 157198 (100.0%) , 0 unresolved %SAMP IMAGE FUNCTION CALLERS 13.2 kernel cpu_search_highest cpu_search_highest:12.0 = sched_idletd:1.2 8.3 kernel ipfw_chk ipfw_check_packet 3.1 myprogram memsetAVX _ZN12TLz4Compress7DoWriteEPKv 2.3 kernel tcp_output tcp_usr_send:1.0 = tcp_do_segment:0.9 > 2) disable checksum on localhost I tried, but nothing has changed. > 3) look at netisr settings. sysctl net.isr o/p and how it looks under > netstat -Q. I am not sure if adding more threads to netisr via What should I look for? > net.isr.numthreads would help. (Note its a loader.conf variable) This netisr load looks parasitical to me (as I noted, moving haproxy to = a separate machine does not burn CPU cycles on netisr, why is localhost = special?) Even if adding more threads to netisr would boost network utilization, = wouldn't those CPU cycles spent for netisr just be a waste of energy? I = have other tasks for these CPU. > > As I said, I am not sure whats up. Just throwing some ideas here. Thanks!=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?EA9AD61B-E709-4387-8D5E-A33E25475D81>