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Date:      Thu, 29 Oct 2015 03:09:10 -0700
From:      Jeremy Chadwick <jdc@koitsu.org>
To:        Miroslav Lachman <000.fbsd@quip.cz>
Cc:        freebsd-stable@freebsd.org
Subject:   Re: stable/10: high load average when box is idle
Message-ID:  <20151029100910.GA52255@icarus.home.lan>
In-Reply-To: <5631EE40.3020404@quip.cz>
References:  <20151027050508.GA7612@icarus.home.lan> <5631EE40.3020404@quip.cz>

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On Thu, Oct 29, 2015 at 11:00:32AM +0100, Miroslav Lachman wrote:
> Jeremy Chadwick wrote on 10/27/2015 06:05:
> >(I am not subscribed to the mailing list, please keep me CC'd)
> >
> >Issue: a stable/10 system that has an abnormally high load average (e.g.
> >0.15, but may be higher depending on other variables which I can't
> >account for) when the machine is definitely idle (i.e. cannot be traced
> >to high interrupt usage per vmstat -i, cannot be traced to a userland
> >process or kernel thread, etc.).
> >
> >This problem has been discussed many times on the FreeBSD mailing lists
> >and the FreeBSD forum (including some folks seeing it on 9.x, but my
> >complaint here is focused on 10.x so please focus there).
> >
> >I'd politely like to request that anyone experiencing this, or who has
> >experienced it (and if you know when it stopped or why, including what
> >you may have done, include that), to chime in on this ticket from 2012
> >(made for 9.x but style of issue still applies; c#5 is quite valid):
> >
> >https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=173541
> >
> >For those still experiencing it, I'd suggest reading c#8 and seeing if
> >sysctl kern.eventtimer.periodic=1 relieves the problem for you.  (At
> >this time I would not suggest leaving that set indefinitely, as it does
> >seem to increase the interrupt rate in cpuX:timer in vmstat -i.  But for
> >me kern.eventtimer.periodic=1 "fixes" the issue)
> 
> Is it on real HW server or in some kind of virtualization? I am seeing load
> 0.5 - 1.2 on three virtual machines in VMware. The machines are without any
> traffic. Just fresh instalation of FreeBSD 10.1 and some services without
> any public content.

I've seen it on both bare-metal and VMs.  Please see c#8 in the ticket;
there's an itemised list of where I've seen it, but I'm sure it's not
limited to just those.

-- 
| Jeremy Chadwick                                   jdc@koitsu.org |
| UNIX Systems Administrator                http://jdc.koitsu.org/ |
| Making life hard for others since 1977.             PGP 4BD6C0CB |




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