Date: Fri, 18 Apr 2008 12:19:57 -0400 (EDT) From: Mike Andrews <mandrews@bit0.com> To: Jeremy Chadwick <koitsu@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: calcru: time went backwards Message-ID: <20080418120530.T98605@beast.int.bit0.com> In-Reply-To: <20080418152957.GA44461@eos.sc1.parodius.com> References: <00df01c89ef8$9733c6d0$c59b5470$@org> <20080415141138.GA33154@mail.scottro.net> <20080415142034.GA80792@eos.sc1.parodius.com> <20080415225159.R54132@thebighonker.lerctr.org> <4808A776.60503@pp.nic.fi> <20080418152957.GA44461@eos.sc1.parodius.com>
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On Fri, 18 Apr 2008, Jeremy Chadwick wrote: > On Fri, Apr 18, 2008 at 04:51:50PM +0300, Pertti Kosunen wrote: >> Larry Rosenman wrote: >>> On Tue, 15 Apr 2008, Jeremy Chadwick wrote: >>>> And what the FAQ doesn't cover is here: >>>> >>>> http://wiki.freebsd.org/JeremyChadwick/Commonly_reported_issues >>>> >>>> * EIST (Intel SpeedStep) incompatibilities with Supermicro PDSMI+ >>>> motherboards (and possibly others) >>>> * Symptom: kernel outputs messages like kernel: calcru: negative >>>> runtime of -XXXXX usec for pid XX >>>> * Workaround: Disable the EIST feature in the BIOS. You can still >>>> achieve ACPI-based processor >>>> frequency throttling by using powerd(8). >>>> * Reference: >>>> http://lists.freebsd.org/pipermail/freebsd-questions/2006-October/133253.html >>> What I find interesting is I hadn't seen these until this kernel update :( >> >> Same problem here with Tyan Toledo i3000R (S5191) motherboard if cpufreq >> module is loaded. >> >> 7.0-RELEASE (AMD64) didn't have this problem. > > Are you absolutely positive about this (re: amd64 not having the > problem)? I can reproduce the issue documented in my Wiki page on i386 > or amd64. The piece that seems to cause it, at least in the case of the > PDSMI+, is EIST being enabled in the BIOS. For what it's worth, I've got five Supermicro PDSMI+ and one PDSMA+ in production, all running amd64, and starting from when I moved from 6.2-STABLE to 7.0-BETA, and continuing through last week's 7.0-STABLE, I started seeing "calcru: runtime went backwards"... messages for about 2-3 minutes after a reboot, then they'd go away on their own. Disabling EIST in the BIOS two days ago made the problem go away on all six systems. The systems are using the ACPI-fast timecounter (the default) except the PDSMA+ uses TSC because it's faster for MySQL... switching between the two didn't make any difference. I figured the reason the errors went away 3 minutes after boot was due to ntpd beating the clock into behaving. I also don't have the cpufreq module loaded. In my case the error messages seemed pretty harmless and the systems have been running great for a long time... both before and after toggling EIST... I only mention it because in my case, it was a slightly different message (always "runtime went backwards" not "negative runtime"), and it did affect 7.0-RELEASE/amd64 for me, and maybe that'll help someone narrow it down...
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