Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755957Ab2KCPlk (ORCPT ); Sat, 3 Nov 2012 11:41:40 -0400 Received: from mail-ia0-f174.google.com ([209.85.210.174]:37483 "EHLO mail-ia0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755404Ab2KCPli (ORCPT ); Sat, 3 Nov 2012 11:41:38 -0400 MIME-Version: 1.0 In-Reply-To: <1351943332.16850.25.camel@maggy.simpson.net> References: <1351942405.16850.23.camel@maggy.simpson.net> <1351943332.16850.25.camel@maggy.simpson.net> From: Michal Zatloukal Date: Sat, 3 Nov 2012 16:40:57 +0100 Message-ID: Subject: Re: Fwd: Nice processes prevent frequency increases - possible scheduler regression (known good in 2.6.35) To: linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1681 Lines: 33 On Sat, Nov 3, 2012 at 12:48 PM, Mike Galbraith wrote: > On Sat, 2012-11-03 at 04:33 -0700, Mike Galbraith wrote: >> On Fri, 2012-11-02 at 21:09 +0100, Michal Zatloukal wrote: >> >> > On the new kernel, the nice processes are never starved - even when >> > starting a tab-laden chromium session, the processes for BOINC keep >> > about 20% CPU each (that is normalized to all CPUs, ie 40% nice load >> > on each core). The problem is, the governor now seems to consider the >> > non-nice task unable to saturate the CPU, and the cores' frequencies >> > are hovering between 1.0 and 1.8 GHz. The scheduler keeps scheduling >> > the nice tasks, and the non-nice tasks are progressing much slower, >> > caused by the lower CPU speed as well as less processing time >> > allocated to them. HD video stutters often, and Chromium takes at >> > least 2-3 times longer to fully load. >> >> Your nice 19 tasks receiving 'too much' CPU when there are other >> runnable tasks around sounds like you have SCHED_AUTOGROUP enabled. > > (forgot to mention: if that's the case, you can add noautogroup to your > kernel command line to turn it off if distro turned it on in .config) > Thanks, Ubuntu's kernel is indeed configured with that option enabled, and passing "noautogroup" at grub restores the previous behaviour. I'm back to happy days again :) BTW, isn't this the "magic 200-line patch" I was reading about ~2 years ago? MZ -- 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/