From owner-freebsd-arch Thu May 17 1:11:58 2001 Delivered-To: freebsd-arch@freebsd.org Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by hub.freebsd.org (Postfix) with ESMTP id 7FC3137B422; Thu, 17 May 2001 01:11:53 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter (localhost [127.0.0.1]) by critter.freebsd.dk (8.11.3/8.11.3) with ESMTP id f4H8BlL10773; Thu, 17 May 2001 10:11:47 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Mike Smith Cc: Bruce Evans , freebsd-questions@FreeBSD.ORG, arch@FreeBSD.ORG Subject: Re: Gettimeofday Again... In-Reply-To: Your message of "Thu, 17 May 2001 01:13:43 PDT." <200105170813.f4H8DhE01424@mass.dis.org> Date: Thu, 17 May 2001 10:11:47 +0200 Message-ID: <10771.990087107@critter> From: Poul-Henning Kamp Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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