From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261385AbULPNum (ORCPT ); Thu, 16 Dec 2004 08:50:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261930AbULPNul (ORCPT ); Thu, 16 Dec 2004 08:50:41 -0500 Received: from clock-tower.bc.nu ([81.2.110.250]:386 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S261385AbULPNuh (ORCPT ); Thu, 16 Dec 2004 08:50:37 -0500 Subject: Re: Time goes crazy in 2.6.9 after long cli [was Re: USB making time drift] From: Alan Cox To: Andrea Arcangeli Cc: Pavel Machek , Zwane Mwaikambo , Con Kolivas , Linux Kernel Mailing List In-Reply-To: <20041216111343.GI28286@dualathlon.random> References: <20041213112853.GS16322@dualathlon.random> <20041213124313.GB29426@atrey.karlin.mff.cuni.cz> <20041213125844.GY16322@dualathlon.random> <20041213191249.GB1052@elf.ucw.cz> <20041214023651.GT16322@dualathlon.random> <20041214095939.GC1063@elf.ucw.cz> <20041214152558.GB16322@dualathlon.random> <20041214220239.GA19221@elf.ucw.cz> <20041216011549.GD6285@elf.ucw.cz> <20041216111343.GI28286@dualathlon.random> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1103201365.3804.2.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Thu, 16 Dec 2004 12:49:27 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Iau, 2004-12-16 at 11:13, Andrea Arcangeli wrote: > Well, I was pretty sure it was reproducible since the PIT and TSC are > standard hw in all machines, it's just the excessive usb irq latency TSC is not by any means standard hw in all machines and it has a whole pile of issues on some of them with the way it varies rate and/or stops. > My suggestion is that first we fix the accuracy of this, and *then* we > consider switching to a one-short timer. Agreed - one shot timers are going to be nearly impossible to use for system time accounting because we keep losing time resetting it.