From owner-cvs-src@FreeBSD.ORG Tue Oct 18 13:47:39 2005 Return-Path: X-Original-To: cvs-src@FreeBSD.org Delivered-To: cvs-src@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C9D2416A41F; Tue, 18 Oct 2005 13:47:39 +0000 (GMT) (envelope-from phk@critter.freebsd.dk) Received: from phk.freebsd.dk (phk.freebsd.dk [130.225.244.222]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6A0AB43D46; Tue, 18 Oct 2005 13:47:39 +0000 (GMT) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (unknown [192.168.48.2]) by phk.freebsd.dk (Postfix) with ESMTP id 90716BC84; Tue, 18 Oct 2005 13:47:37 +0000 (UTC) To: Andrew Gallatin From: "Poul-Henning Kamp" In-Reply-To: Your message of "Tue, 18 Oct 2005 09:44:02 EDT." <20051018094402.A29138@grasshopper.cs.duke.edu> Date: Tue, 18 Oct 2005 15:47:36 +0200 Message-ID: <68671.1129643256@critter.freebsd.dk> Sender: phk@critter.freebsd.dk Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, David Xu , cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/amd64/amd64 cpu_switch.S machdep.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Oct 2005 13:47:40 -0000 In message <20051018094402.A29138@grasshopper.cs.duke.edu>, Andrew Gallatin wri tes: >It is a shame we can't find a way to use the TSC as a timecounter on >SMP systems. It seems that about 40% of the context switch time is >spent just waiting for the PIO read of the ACPI-fast or i8254 to >return. No, the shame is that the scheduler tries to partition time rather than cpu cycles because that approximation got goldplated in some random standard years back. -- 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.