Date: Thu, 4 Jun 2020 14:16:04 +0200 From: Gordon Bergling <gbergling@googlemail.com> To: Daniel Ebdrup Jensen <debdrup@freebsd.org>, freebsd-hackers@freebsd.org Subject: Re: Constant load of 1 on a recent 12-STABLE Message-ID: <20200604121604.GA23413@lion.0xfce3.net> In-Reply-To: <20200603204511.6qmsub2gqc44jkjw@nerd-thinkpad.local> References: <20200603101607.GA80381@lion.0xfce3.net> <c18664e8-b4e3-1402-48ed-3a02dc36ce29@freebsd.org> <20200603202929.GA65032@lion.0xfce3.net> <20200603204511.6qmsub2gqc44jkjw@nerd-thinkpad.local>
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Hi Daniel, On Wed, Jun 03, 2020 at 10:45:11PM +0200, Daniel Ebdrup Jensen wrote: > On Wed, Jun 03, 2020 at 10:29:29PM +0200, Gordon Bergling via freebsd-hackers wrote: > >On Wed, Jun 03, 2020 at 03:13:47PM -0400, Allan Jude wrote: > >> On 2020-06-03 06:16, Gordon Bergling via freebsd-hackers wrote: > >> > since a while I am seeing a constant load of 1.00 on 12-STABLE, > >> > but all CPUs are shown as 100% idle in top. > >> > > >> > Has anyone an idea what could caused this? > >> > > >> > The load seems to be somewhat real, since the buildtimes on this > >> > machine for -CURRENT increased from about 2 hours to 3 hours. > >> > > >> > This a virtualized system running on Hyper-V, if that matters. > >> > > >> > Any hints are more then appreciated. > >> > >> Try running 'top -SP' and see if that shows a specific CPU being busy, > >> or a specific process using CPU time > > > >Below is the output of 'top -SP'. The only relevant process / thread that is > >relatively constant consumes CPU time seams to be 'zfskern'. > > > >----------------------------------------------------------------------------- > >last pid: 68549; load averages: 1.10, 1.19, 1.16 up 0+14:59:45 22:17:24 > >67 processes: 2 running, 64 sleeping, 1 waiting > >CPU 0: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle > >CPU 1: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle > >CPU 2: 0.0% user, 0.0% nice, 0.4% system, 0.0% interrupt, 99.6% idle > >CPU 3: 0.0% user, 0.0% nice, 0.0% system, 0.0% interrupt, 100% idle > >Mem: 108M Active, 4160M Inact, 33M Laundry, 3196M Wired, 444M Free > >ARC: 1858M Total, 855M MFU, 138M MRU, 96K Anon, 24M Header, 840M Other > > 461M Compressed, 1039M Uncompressed, 2.25:1 Ratio > >Swap: 2048M Total, 2048M Free > > > > PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND > > 11 root 4 155 ki31 0B 64K RUN 0 47.3H 386.10% idle > > 8 root 65 -8 - 0B 1040K t->zth 0 115:39 12.61% zfskern > >------------------------------------------------------------------------------- > > > >The only key performance indicator that is relatively high IMHO, for a > >non-busy system, are the context switches, that vmstat has reported. > > > >------------------------------------------------------------------------------- > >procs memory page disks faults cpu > >r b w avm fre flt re pi po fr sr da0 da1 in sy cs us sy id > >0 0 0 514G 444M 7877 2 7 0 9595 171 0 0 0 4347 43322 17 2 81 > >0 0 0 514G 444M 1 0 0 0 0 44 0 0 0 121 40876 0 0 100 > >0 0 0 514G 444M 0 0 0 0 0 40 0 0 0 133 42520 0 0 100 > >0 0 0 514G 444M 0 0 0 0 0 40 0 0 0 120 43830 0 0 100 > >0 0 0 514G 444M 0 0 0 0 0 40 0 0 0 132 42917 0 0 100 > >-------------------------------------------------------------------------------- > > > >Any other ideas what could generate that load? > > > I seem to recall bde@ (may he rest in peace) mentioning that the ULE scheduler > had some weirdness around sometimes generating a higher load number (one of my > systems would regularily idle at 0.60, but doesn't do it on 12.1 so I gave up > trying to debug it) for no apparent reason, and it maybe being linked to how > WCPU and CPU don't differ on the ULE scheduler? > > Have you tried setting the kern.eventtimer.periodic sysctl to 1? > > Yours, > Daniel Ebdrup Jensen thanks for the hint regarding the kern.eventtimer.periodic sysctl, but it doesn't changed anything. I had running with enabled for about 8 hours. I try now to collect more information like Allan has suggested. Best regards, Gordon -- Gordon Bergling Mobile: +49 170 23 10 948 Web: https://www.gordons-perspective.com/ Mail: gbergling@gmail.com Think before you print!
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