Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266912AbUIETOs (ORCPT ); Sun, 5 Sep 2004 15:14:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266914AbUIETOs (ORCPT ); Sun, 5 Sep 2004 15:14:48 -0400 Received: from mx2.elte.hu ([157.181.151.9]:57801 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S266912AbUIETNP (ORCPT ); Sun, 5 Sep 2004 15:13:15 -0400 Date: Sun, 5 Sep 2004 21:12:27 +0200 From: Ingo Molnar To: Lee Revell Cc: Florian Schmidt , "K.R. Foley" , linux-kernel , felipe_alfaro@linuxmail.org Subject: Re: [patch] voluntary-preempt-2.6.9-rc1-bk12-R5 Message-ID: <20040905191227.GA29797@elte.hu> References: <20040903120957.00665413@mango.fruits.de> <20040904195141.GA6208@elte.hu> <20040905140249.GA23502@elte.hu> <1094408203.4445.5.camel@krustophenia.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1094408203.4445.5.camel@krustophenia.net> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1218 Lines: 31 * Lee Revell wrote: > Ok, first new one in a while. This was with -R0, but I haven't seen > anyone else report it. Let me know if you need the complete trace. > > preemption latency trace v1.0.2 > ------------------------------- > latency: 511 us, entries: 951 (951) > ----------------- > | task: dbench/4810, uid:1000 nice:0 policy:0 rt_prio:0 > ----------------- > => started at: kill_pg_info+0x10/0x50 > => ended at: kill_pg_info+0x2e/0x50 > =======> > 00000001 0.000ms (+0.000ms): kill_pg_info (sys_kill) > 00000001 0.000ms (+0.000ms): __kill_pg_info (kill_pg_info) > 00000001 0.000ms (+0.000ms): find_pid (__kill_pg_info) this is quite hard to fix - lots of processes were SIGKILL-ed (or SIGTERM-ed) and the signal semantics require us to deliver signals atomically. The only fix would be to turn the signal locks into semaphores but that's quite hard. (it's also a bit problematic for interrupt-delivered signals.) Ingo - 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/