From owner-freebsd-current@FreeBSD.ORG Sat Jul 10 07:12:45 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 03B4A16A4CE for ; Sat, 10 Jul 2004 07:12:45 +0000 (GMT) Received: from smtp003.bizmail.yahoo.com (smtp003.bizmail.yahoo.com [216.136.130.195]) by mx1.FreeBSD.org (Postfix) with SMTP id D928E43D53 for ; Sat, 10 Jul 2004 07:12:44 +0000 (GMT) (envelope-from noackjr@alumni.rice.edu) Received: from unknown (HELO optimator.noacks.org) (noackjr@supercrime.org@70.240.179.251 with login) by smtp003.bizmail.yahoo.com with SMTP; 10 Jul 2004 07:12:44 -0000 Received: from localhost (localhost [127.0.0.1]) by optimator.noacks.org (Postfix) with ESMTP id 840F8628C; Sat, 10 Jul 2004 02:12:43 -0500 (CDT) Received: from optimator.noacks.org ([127.0.0.1]) by localhost (optimator.noacks.org [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 37396-01-2; Sat, 10 Jul 2004 02:12:41 -0500 (CDT) Received: from compgeek.noacks.org (compgeek [192.168.1.10]) by optimator.noacks.org (Postfix) with ESMTP id 7140E6101; Sat, 10 Jul 2004 02:12:41 -0500 (CDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by compgeek.noacks.org (8.12.11/8.12.11) with ESMTP id i6A7CdbC081196; Sat, 10 Jul 2004 02:12:41 -0500 (CDT) (envelope-from noackjr@alumni.rice.edu) Message-ID: <40EF96E7.3090608@alumni.rice.edu> Date: Sat, 10 Jul 2004 02:12:39 -0500 From: Jon Noack User-Agent: Mozilla Thunderbird 0.7.1 (X11/20040629) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ariff Abdullah References: <20040710150620.7595b207.skywizard@MyBSD.org.my> In-Reply-To: <20040710150620.7595b207.skywizard@MyBSD.org.my> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at noacks.org cc: freebsd-current@freebsd.org cc: Robert Watson Subject: Re: Native preemption is the culprit [was Re: today's CURRENT lockups] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: noackjr@alumni.rice.edu List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Jul 2004 07:12:45 -0000 On 07/10/04 02:06, Ariff Abdullah wrote: > On Sat, 10 Jul 2004 01:18:06 -0400 (EDT) > Robert Watson wrote: >> FYI, UP+SCHED_ULE with PREEMPTION hung within three seconds of >> starting the benchmark. Without PREEMPTION it seems to run fine. >> >> So it looks like either PREEMPTION has a problem, or it's >> triggering an existing problem elsewhere. If it's only one problem, >> it seems not to depend on either SMP/UP or the scheduler choice. If >> it's multiple problems, who knows :-). As the MySQL test relies on >> threading, we could be looking at an edge case involving threading >> and scheduling/preemption-- the other reports I've seen mention >> X11/KDE, which would also involve threading. On the other hand, it >> could just be load. Tomorrow I'll load up a box with non-threaded >> apps and see what happens. > > I'm suspecting bad combination between threaded apps and current > native preemption, either the preemption itself, or threads. Running > current kernel without any threaded apps turns up nothing suspicious. > Once the threaded apps started, it's like sending the entire system to > the death row. > > I'm reverting following files to pre-July 2 to achive solid stability: > > sys/sys/interrupt.h - v1.27 > sys/kern/kern_intr.c - v1.110 > sys/i386/i386/intr_machdep.c - v1.6 > sys/kern/sched_ule.c - v1.109 Note that I haven't run across any issues after just reverting sys/kern/sched_ule.c to rev. 1.113. The same workload (X11/KDE/etc.) that crashes native preemption quite quickly has been running solidly for over 14 hours now. Jon