Date: Thu, 21 Dec 2006 07:37:33 +0300 From: Yar Tikhiy <yar@comp.chem.msu.su> To: V??clav Haisman <V.Haisman@sh.cvut.cz> Cc: freebsd-stable@freebsd.org Subject: Re: negative runtime etc., the story continues Message-ID: <20061221043733.GA63112@comp.chem.msu.su> In-Reply-To: <45886C87.8020405@sh.cvut.cz> References: <45886C87.8020405@sh.cvut.cz>
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On Tue, Dec 19, 2006 at 11:49:43PM +0100, V??clav Haisman wrote: > Hi, > I wrote about how FreeBSD 6.1 RC1, with latest RELENG_6 kernel, prints loads > of "calcru: runtime went backwards..." and "calcru: negative runtime..." > messages when the FreeBSD runs as virtual server under Microsoft Virtual > Server 2006 R2. When I wrote this I was compiling and installing lots of > packages, setting up the OS. Now that it is idle I have noticed one quite bad > thing. Any process that sleeps on timer or sleep() call will wake up much > later than it should. For example, when I start top there should be two > seconds delay between updates of the screen. It takes up to 20 seconds! But > when there is compilation running or something else CPU intensive, the timer > seems to work fine. > > I even tried setting different kern.timecounter.hardware (TSC, ACPI-safe, > i8254) and kern.hz (to lower than the default 1000) but that did not help a bit. > > Is there anything I can do to get rid of the calcru messages apart from > reinstalling to real hardware? Last time I was trying to run FreeBSD as a guest OS in MS VS, I found that TSC would work the best, but only if I made sure that the TSC frequency was correct. For some weird reason, the frequency initially detected by the kernel was totally bogus and changing from one boot to another, so I just estimated it from cpu-z output in the host OS, and it fairly worked. I still couldn't get rid of the annoying warnings, especially when under load. -- Yar
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