Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755651AbYCQVIu (ORCPT ); Mon, 17 Mar 2008 17:08:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752292AbYCQVIn (ORCPT ); Mon, 17 Mar 2008 17:08:43 -0400 Received: from 41-052.adsl.zetnet.co.uk ([194.247.41.52]:34463 "EHLO mail.esperi.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751675AbYCQVIn (ORCPT ); Mon, 17 Mar 2008 17:08:43 -0400 To: Jeff Dike Cc: clowncoder , user-mode-linux-devel@lists.sourceforge.net, linux-kernel Mailing List , Thomas Gleixner Subject: Re: [2.6.24.x] UML select()/poll() oversleeping reproducibly References: <47B34BA0.30006@club-internet.fr> <20080214003853.GA15952@c2.user-mode-linux.org> <47B4BDCD.4080605@club-internet.fr> <20080215160205.GA6082@c2.user-mode-linux.org> <47B5CE40.9000005@club-internet.fr> <20080215184650.GA8810@c2.user-mode-linux.org> <87y78kx640.fsf_-_@hades.wkstn.nix> <20080317193415.GA12234@c2.user-mode-linux.org> From: Nix Emacs: ... it's not just a way of life, it's a text editor! Date: Mon, 17 Mar 2008 21:08:16 +0000 In-Reply-To: <20080317193415.GA12234@c2.user-mode-linux.org> (Jeff Dike's message of "Mon, 17 Mar 2008 15:34:15 -0400") Message-ID: <87k5k112kf.fsf@hades.wkstn.nix> User-Agent: Gnus/5.1008 (Gnus v5.10.8) XEmacs/21.5-b28 (linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-DCC-dcc1-Metrics: hades 1182; Body=5 Fuz1=5 Fuz2=5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1666 Lines: 53 On 17 Mar 2008, Jeff Dike verbalised: > Below is the same patch with another kluge, which cuts down the > requested sleep by 10% in hopes of getting the actual sleep closer to > what's wanted. Eeuuuuw. :) > This is unusable in anything resembling mainline, but I'd like to see > how your various systems react to it. I'm getting very close to the > sleeps I asked for (with slight undersleeping, which is a bug). OK. Tests on host with clocksource pit: bash-3.2# bin/select-sleep 5 Slept for 5 seconds. bash-3.2# bin/select-sleep 10 Slept for 11 seconds. bash-3.2# bin/select-sleep 30 Slept for 31 seconds. bash-3.2# bin/select-sleep 60 Slept for 61 seconds. ... so much better than the 4x error without this patch. Tests on host with clocksource tsc: bash-3.2# bin/select-sleep 5 Slept for 5 seconds. bash-3.2# bin/select-sleep 10 Slept for 10 seconds. bash-3.2# bin/select-sleep 30 Slept for 30 seconds. bash-3.2# bin/select-sleep 60 Slept for 61 seconds. Distinctly better than without this patch. (Am I the only person who finds it strange that (some) clocksource hackers are arguing about accuracy problems in the ppm range while we're glad to get an error of `only' single seconds per minute out of it? Maybe next year we can invent the `pendulum' clocksource :) ) -- `The rest is a tale of post and counter-post.' --- Ian Rawlings describes USENET -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/