Date: Mon, 07 Apr 2003 01:30:23 +0200 From: Dag-Erling Smorgrav <des@ofug.org> To: "Poul-Henning Kamp" <phk@phk.freebsd.dk> Cc: Nate Lawson <nate@root.org> Subject: Re: cvs commit: src/sys/conf options.i386 src/sys/i386/i386 tsc.c src/sys/i386/conf NOTES Message-ID: <xzphe9bdx0w.fsf@flood.ping.uio.no> In-Reply-To: <30949.1049666639@critter.freebsd.dk> ("Poul-Henning Kamp"'s message of "Mon, 07 Apr 2003 00:03:59 %2B0200") References: <30949.1049666639@critter.freebsd.dk>
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"Poul-Henning Kamp" <phk@phk.freebsd.dk> writes: > In message <xzpof3js45j.fsf@flood.ping.uio.no>, Dag-Erling Smorgrav writes: > > On most SMP systems, the > > PIIX timecounter is automatically selected by virtue of being > > discovered last. > It is specifically discovered last because it should be used if > at all possible. It's more precise than the TSC (mostly because the TSC calibration code sucks), but if one is willing to sacrifice a small amount of precision for performance, then the TSC is probably better, I think. > There is a big difference if you get to use "ACPI-fast" (correctly > implemented hardware) instead of "ACPI-safe" (buggy hardware). Unfortunately, ACPI-fast is not available on my system. DES -- Dag-Erling Smorgrav - des@ofug.org
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