Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751634AbWCUM7V (ORCPT ); Tue, 21 Mar 2006 07:59:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751636AbWCUM7U (ORCPT ); Tue, 21 Mar 2006 07:59:20 -0500 Received: from willy.net1.nerim.net ([62.212.114.60]:50443 "EHLO willy.net1.nerim.net") by vger.kernel.org with ESMTP id S1751631AbWCUM7U (ORCPT ); Tue, 21 Mar 2006 07:59:20 -0500 Date: Tue, 21 Mar 2006 13:59:00 +0100 From: Willy Tarreau To: Mike Galbraith Cc: Ingo Molnar , lkml , Andrew Morton , Con Kolivas , bugsplatter@gmail.com Subject: Re: interactive task starvation Message-ID: <20060321125900.GA25943@w.ods.org> References: <1142592375.7895.43.camel@homer> <1142615721.7841.15.camel@homer> <1142838553.8441.13.camel@homer> <20060321064723.GH21493@w.ods.org> <1142927498.7667.34.camel@homer> <20060321091353.GA25248@w.ods.org> <20060321091422.GA9207@elte.hu> <20060321111552.GA25651@w.ods.org> <20060321111850.GA2776@elte.hu> <1142942878.7807.9.camel@homer> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1142942878.7807.9.camel@homer> User-Agent: Mutt/1.5.10i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2592 Lines: 91 On Tue, Mar 21, 2006 at 01:07:58PM +0100, Mike Galbraith wrote: > On Tue, 2006-03-21 at 12:18 +0100, Ingo Molnar wrote: > > > great work by Mike! One detail: i'd like there to be just one default > > throttling value, i.e. no grace_g tunables [so that we have just one > > default scheduler behavior]. Is the default grace_g[12] setting good > > enough for your workload? The default values are infinitely better than mainline, but it is still a huge improvement to reduce them (at least grace_g2) : default : grace_g1=10, grace_g2=14400, loadavg oscillating between 7 and 12 : willy@wtap:~$ time ls -la /data/src/tmp/|wc 2271 18250 212211 real 0m5.759s user 0m0.028s sys 0m0.008s willy@wtap:~$ time ls -la /data/src/tmp/|wc 2271 18250 212211 real 0m3.476s user 0m0.020s sys 0m0.016s willy@wtap:~$ I can still observe some occasionnal pauses of 1 to 3 seconds (once to 4 times per minute). - grace_g2 set to 0, load converges to a stable 8 : willy@wtap:~$ time ls -la /data/src/tmp/|wc 2271 18250 212211 real 0m0.441s user 0m0.036s sys 0m0.004s willy@wtap:~$ time ls -la /data/src/tmp/|wc 2271 18250 212211 real 0m0.400s user 0m0.032s sys 0m0.008s I can still observe some rare cases of 1 second pauses (once or twice per minute). - grace_g2 and grace_g1 set to zero : willy@wtap:~$ time ls -la /data/src/tmp/|wc 2271 18250 212211 real 0m0.214s user 0m0.028s sys 0m0.008s willy@wtap:~$ time ls -la /data/src/tmp/|wc 2271 18250 212211 real 0m0.193s user 0m0.032s sys 0m0.008s => I never observe any pause, and the numbers above sometimes even get lower (around 75 ms). I have also tried injecting traffic on my proxy, and at 16000 hits/s, its does not impact overall system's responsiveness, whatever (g1,g2). > I can make the knobs compile time so we don't see random behavior > reports, but I don't think they can be totally eliminated. Would that > be sufficient? > > If so, the numbers as delivered should be fine for desktop boxen I > think. People who are building custom kernels can bend to fit as > always. That would suit me perfectly. I think I would set them both to zero. It's not clear to me what workload they can help, it seems that they try to allow a sometimes unfair scheduling. > -Mike Cheers, Willy - 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/