From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1JbMZS-0000qQ-Ho for user-mode-linux-devel@lists.sourceforge.net; Mon, 17 Mar 2008 14:08:38 -0700 Received: from 41-052.adsl.zetnet.co.uk ([194.247.41.52] helo=mail.esperi.org.uk ident=user43400) by mail.sourceforge.net with esmtp (Exim 4.44) id 1JbMZP-0006ws-Rx for user-mode-linux-devel@lists.sourceforge.net; Mon, 17 Mar 2008 14:08:38 -0700 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 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> MIME-Version: 1.0 Subject: Re: [uml-devel] [2.6.24.x] UML select()/poll() oversleeping reproducibly List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-bounces@lists.sourceforge.net Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Jeff Dike Cc: Thomas Gleixner , linux-kernel Mailing List , user-mode-linux-devel@lists.sourceforge.net 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 ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel