Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761098AbZDQNuh (ORCPT ); Fri, 17 Apr 2009 09:50:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760751AbZDQNuF (ORCPT ); Fri, 17 Apr 2009 09:50:05 -0400 Received: from smtp.ultrahosting.com ([74.213.174.254]:35285 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760926AbZDQNuD (ORCPT ); Fri, 17 Apr 2009 09:50:03 -0400 Date: Fri, 17 Apr 2009 09:42:30 -0400 (EDT) From: Christoph Lameter X-X-Sender: cl@qirst.com To: Peter Zijlstra cc: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: Scheduler regression: Too frequent timer interrupts(?) In-Reply-To: <1239951613.23397.4107.camel@laptop> Message-ID: References: <1239951613.23397.4107.camel@laptop> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 832 Lines: 22 On Fri, 17 Apr 2009, Peter Zijlstra wrote: > This has never been true afaikt, as long as we have a task running, we > take the interrupt, I just looked at the .22 code and that certainly > expects the scheduler_tick() to be called when there is a running > process. > > Also, look at /proc/interrupts if you want to determine interrupt > frequency. I am mainly interested in limited the number and length of cpu holdoffs. If the timer interrupt is always taken then it must take less than 1 usec in certain versions of the kernel in order to not show up in the statistics gathered. -- 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/