Date: Thu, 06 Feb 2003 23:04:43 +0100 From: phk@freebsd.org To: Peter Wemm <peter@wemm.org> Cc: Bruce Evans <bde@zeta.org.au>, "Greg 'groggy' Lehey" <grog@freebsd.org>, all-committers@freebsd.org, legacy-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/i386/include clock.h src/sys/i386/i386 tsc.c Message-ID: <2855.1044569083@critter.freebsd.dk> In-Reply-To: Your message of "Thu, 06 Feb 2003 14:02:09 PST." <20030206220209.EDA882A89E@canning.wemm.org>
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In message <20030206220209.EDA882A89E@canning.wemm.org>, Peter Wemm writes: >phk@freebsd.org wrote: >> In message <20030206174018.R72201-100000@gamplex.bde.org>, Bruce Evans writes > : >> >> >However, precise measurements of these clocks turn out to be essentially >> >useless except probably for phk's nonstandard hardware, since the >> >accuracy of these clocks is much worse than their precision. Drift of >> >10-100 parts per million for a 10 degree temperature change is normal. >> >So calibrations more precise than this are not useful. >> >> Actually, things have improved, and motherboard crystals are now >> generally no worse than +/-1 PPM/K. > >For newer motherboards. :-) I think for anything after PII, it was the new clock regime which put tighter limits on jitter that did it I think. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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