Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752391AbZIIJR5 (ORCPT ); Wed, 9 Sep 2009 05:17:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752024AbZIIJR4 (ORCPT ); Wed, 9 Sep 2009 05:17:56 -0400 Received: from viefep18-int.chello.at ([62.179.121.38]:18136 "EHLO viefep18-int.chello.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751775AbZIIJR4 (ORCPT ); Wed, 9 Sep 2009 05:17:56 -0400 X-SourceIP: 213.93.53.227 Subject: Re: BFS vs. mainline scheduler benchmarks and measurements From: Peter Zijlstra To: Nikos Chantziaras Cc: Mike Galbraith , Ingo Molnar , Jens Axboe , Con Kolivas , linux-kernel@vger.kernel.org In-Reply-To: <4AA76FD2.1050103@arcor.de> References: <20090906205952.GA6516@elte.hu> <20090907094953.GP18599@kernel.dk> <20090907115750.GW18599@kernel.dk> <20090907141458.GD24507@elte.hu> <20090907173846.GB18599@kernel.dk> <20090907204458.GJ18599@kernel.dk> <20090908091304.GQ18599@kernel.dk> <1252423398.7746.97.camel@twins> <20090908203409.GJ18599@kernel.dk> <20090909061308.GA28109@elte.hu> <1252486344.28645.18.camel@marge.simson.net> <4AA76FD2.1050103@arcor.de> Content-Type: text/plain Date: Wed, 09 Sep 2009 11:17:49 +0200 Message-Id: <1252487869.7746.181.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1327 Lines: 34 On Wed, 2009-09-09 at 12:05 +0300, Nikos Chantziaras wrote: > Thank you for mentioning min_granularity. After: > > echo 10000000 > /proc/sys/kernel/sched_latency_ns > echo 2000000 > /proc/sys/kernel/sched_min_granularity_ns You might also want to do: echo 2000000 > /proc/sys/kernel/sched_wakeup_granularity_ns That affects when a newly woken task will preempt an already running task. > I can clearly see an improvement: animations that are supposed to be > fluid "skip" much less now, and in one occasion (simply moving the video > window around) have been eliminated completely. However, there seems to > be a side effect from having CONFIG_SCHED_DEBUG enabled; things seem to > be generally a tad more "jerky" with that option enabled, even when not > even touching the latency and granularity defaults. There's more code in the scheduler with that enabled but unless you've got a terrible high ctx rate that really shouldn't affect things. Anyway, you can always poke at these numbers in the code, and like Mike did, kill sched_init_granularity(). -- 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/