Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751594Ab3G3L7Q (ORCPT ); Tue, 30 Jul 2013 07:59:16 -0400 Received: from merlin.infradead.org ([205.233.59.134]:46316 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750906Ab3G3L7O (ORCPT ); Tue, 30 Jul 2013 07:59:14 -0400 Date: Tue, 30 Jul 2013 13:59:05 +0200 From: Peter Zijlstra To: Ethan Zhao Cc: Thomas Gleixner , Ingo Molnar , LKML , johlstei@codeaurora.org, Yinghai Lu , Jin Feng Subject: Re: [PATCH V3]hrtimer: Fix a performance regression by disable reprogramming in remove_hrtimer Message-ID: <20130730115905.GS3008@twins.programming.kicks-ass.net> References: <1374955447-5051-1-git-send-email-ethan.kernel@gmail.com> <20130730093519.GP3008@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 926 Lines: 23 On Tue, Jul 30, 2013 at 07:44:03PM +0800, Ethan Zhao wrote: > Got it. > what tglx and you mean > > > So the expensive thing maybe not inside the schedule(), but could > outside the scheduler(), the more bigger forever loop. > > This is one part of what I am facing. Right, so it would be good if you could further diagnose the problem so we can come up with a solution that cures the problem while retaining the current 'desired' properties. The patch you pinpointed caused a regression in that it would wake from NOHZ mode far too often. Could it be that the now longer idle sections cause your CPU to go into deeper idle modes and you're suffering from idle-exit latencies? -- 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/