From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261156AbULMUxz (ORCPT ); Mon, 13 Dec 2004 15:53:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261389AbULMUui (ORCPT ); Mon, 13 Dec 2004 15:50:38 -0500 Received: from gprs215-194.eurotel.cz ([160.218.215.194]:12161 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S261156AbULMUt4 (ORCPT ); Mon, 13 Dec 2004 15:49:56 -0500 Date: Mon, 13 Dec 2004 21:49:33 +0100 From: Pavel Machek To: john stultz Cc: Andrea Arcangeli , Zwane Mwaikambo , Con Kolivas , lkml Subject: Re: dynamic-hz Message-ID: <20041213204933.GA4693@elf.ucw.cz> References: <41BCD5F3.80401@kolivas.org> <20041212234331.GO16322@dualathlon.random> <20041213002751.GP16322@dualathlon.random> <20041213112853.GS16322@dualathlon.random> <20041213124313.GB29426@atrey.karlin.mff.cuni.cz> <20041213125844.GY16322@dualathlon.random> <20041213191249.GB1052@elf.ucw.cz> <1102970039.1281.415.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1102970039.1281.415.camel@cog.beaverton.ibm.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > > But that does not matter, right? Yes, one-shot timer will not fire > > > > exactly at right place, but as long as you are reading TSC and basing > > > > next shot on current time, error should not accumulate. > > > > > > As said in the rest of the message, the error (or some other error) > > > accumulates heavily today in the tick-loss compensation/adjustment > > > algorithm in arch/i386/kernel/timers/timer_tsc.c, so I'm sceptical > > > about > > > > I do not see how it should accumulate. Lets have working TSC. You want > > to emulate fixed-period timer with single-shot timer. > > Its caused by the fact that we don't use the the TSC to accumulate time. > We are instead interpolating between timer ticks and the TSC, where Yes, it was supposed to be simple, so that Andrea understands that there's nothing inherently broken with single-shot timers. Pavel -- People were complaining that M$ turns users into beta-testers... ...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!