Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945997AbXBBRku (ORCPT ); Fri, 2 Feb 2007 12:40:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1945998AbXBBRku (ORCPT ); Fri, 2 Feb 2007 12:40:50 -0500 Received: from gateway-1237.mvista.com ([63.81.120.158]:31595 "EHLO gateway-1237.mvista.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945997AbXBBRkt (ORCPT ); Fri, 2 Feb 2007 12:40:49 -0500 Subject: Re: 2.6.20-rc6-mm3 From: Daniel Walker To: Andrew Morton Cc: linux-kernel@vger.kernel.org In-Reply-To: <20070129204528.eb8d695e.akpm@osdl.org> References: <20070129204528.eb8d695e.akpm@osdl.org> Content-Type: text/plain Date: Fri, 02 Feb 2007 09:39:16 -0800 Message-Id: <1170437956.9781.241.camel@imap.mvista.com> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2.1 (2.8.2.1-3.fc6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1782 Lines: 42 On Mon, 2007-01-29 at 20:45 -0800, Andrew Morton wrote: > Temporarily at > > http://userweb.kernel.org/~akpm/2.6.20-rc6-mm3/ > > Will appear later at > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.20-rc6/2.6.20-rc6-mm3/ > I was running likely profiling and I noticed that when I turn on the "tickless" option I get the following line, +unlikely | 21111208| 9367278 need_resched()@:include/linux/sched.h@1597 This means that this line is 21111208 true, and 9367278 false. This existed on bootup, and stayed after about 7 hours of runtime (mostly idle). Since need_resched is a "static inline" there are multiple instances of need_resched() in the kernel. If I turn off the "tickless" feature this wrong unlikely disappears, and the output looks like this, unlikely | 0| 169 need_resched()@:include/linux/sched.h@1597 unlikely | 0| 94 need_resched()@:include/linux/sched.h@1597 unlikely | 0| 63 need_resched()@:include/linux/sched.h@1597 unlikely | 0| 19 need_resched()@:include/linux/sched.h@1597 unlikely | 0| 379 need_resched()@:include/linux/sched.h@1597 unlikely | 1| 202596 need_resched()@:include/linux/sched.h@1597 unlikely | 7| 205929 need_resched()@:include/linux/sched.h@1597 unlikely | 6461| 271690 need_resched()@:include/linux/sched.h@1597 Only a little after boot. I suppose this could be a natural side effect of the tickless feature but I thought I would report it anyway. Daniel - 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/