From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759257Ab1FWKpL (ORCPT ); Thu, 23 Jun 2011 06:45:11 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:55648 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759157Ab1FWKpJ (ORCPT ); Thu, 23 Jun 2011 06:45:09 -0400 Date: Thu, 23 Jun 2011 12:44:55 +0200 From: Ingo Molnar To: Tejun Heo Cc: Thomas Gleixner , LKML , Peter Zijlstra , Jens Axboe , Linus Torvalds Subject: Re: [patch 4/4] sched: Distangle worker accounting from rq->lock Message-ID: <20110623104455.GA9274@elte.hu> References: <20110622174659.496793734@linutronix.de> <20110622174919.135236139@linutronix.de> <20110623083722.GF30101@htj.dyndns.org> <20110623101541.GL30101@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110623101541.GL30101@htj.dyndns.org> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Tejun Heo wrote: > The patch description is simply untrue. It does affect how wq > behaves under heavy CPU load. The effect might be perfectly okay > but more likely it will result in subtle suboptimal behaviors under > certain load situations which would be difficult to characterize > and track down. Again, the trade off (mostly killing of > ttwu_local) could be okay but you can't get away with just claiming > "there's no harm". Well, either it can be measured or not. If you can suggest a specific testing method to Thomas, please do. Thanks, Ingo