Date: Thu, 17 May 2001 10:11:47 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Mike Smith <msmith@FreeBSD.ORG> Cc: Bruce Evans <bde@zeta.org.au>, freebsd-questions@FreeBSD.ORG, arch@FreeBSD.ORG Subject: Re: Gettimeofday Again... Message-ID: <10771.990087107@critter> In-Reply-To: Your message of "Thu, 17 May 2001 01:13:43 PDT." <200105170813.f4H8DhE01424@mass.dis.org>
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In message <200105170813.f4H8DhE01424@mass.dis.org>, Mike Smith writes: >> > I don't change the timercounter method defaults, and I sure hope you >> > aren't advocating that people change their timecounter defaults. If >> > the TSC is a reasonable default, the system should figure it out and >> > use it without requiring intervention. >> >> It's only a reasonable default if apm (or possibly acpica) is configured >> (and used). > >The TSC is never a reasonable default; there is no good way to be certain >that the TSC is and/or will remain stable. Even with ACPI, you can't be >entirely sure. Right. I have tried some hybrid schemes where the TSC is interpolating between i8254 interrupts, but it is all but impossible to maintain continuity on a clock-throttling laptop... -- 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 freebsd-arch" in the body of the message
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