Date: Mon, 03 Jan 2011 13:21:10 +0200 From: Alexander Motin <mav@FreeBSD.org> To: "Matthew D. Fuller" <fullermd@over-yonder.net> Cc: current@freebsd.org Subject: Re: Oddities in -current post-eventtimer Message-ID: <4D21B126.1020207@FreeBSD.org> In-Reply-To: <20110103102853.GA89454@over-yonder.net> References: <20110103102853.GA89454@over-yonder.net>
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On 03.01.2011 12:28, Matthew D. Fuller wrote: > OK, this has happened a couple times now. I'm running a mid-Oct > -CURRENT, and at around 25 days uptime (not exact but consistently in > that vicinity), things start getting very choppy. It's easily visible > in playing videos; things get very jerky and slow, but all sorts of > things start acting like they're happening in little chunks of time; > keyboard repeats get very slow, things that often take notable time > take much more, etc. It's accompanied by a big spat of "calcru: > runtime went backwards" messages (presumably just another symptom). > > The only fix I've found is to reboot, and then it's good for another > 25ish days. As a workaround, enabling kern.eventtimer.idletick sets > things rightish. A look at the interrupts turns up a hint; while > vmstat says the overall average for cpu0 is just under 300/s, systat > -vmstat shows that it's currnetly running around 20-some. The other > CPU's also settle at much lower levels. > > Another more tiring workaround is just slinging the mouse around real > fast; that seems to hint to the system to keep checking stuff. > Watching systat, that doesn't seem to bring the cpuX interrupt rate up > very much, but the videos start playing smoothly. > > FreeBSD 9.0-CURRENT #0 r214107: Wed Oct 20 06:25:50 CDT 2010 > Quad-core running amd64. Symptoms look very alike to ones fixed at r214597 on 2010-10-31: Fix callout_tickstofirst() behavior after signed integer ticks overflow. This should fix callout precision drop to 1/4s after 25 days of uptime with HZ = 1000. -- Alexander Motin
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