Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 21 Jan 2003 00:01:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 21 Jan 2003 00:01:23 -0500 Received: from dhcp34.trinity.linux.conf.au ([130.95.169.34]:2944 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id ; Tue, 21 Jan 2003 00:01:22 -0500 Subject: Re: spinlock efficiency problem [was 2.5.57 IO slowdown with CONFIG_PREEMPT enabled) From: Alan To: Joe Korty Cc: Linux Kernel Mailing List In-Reply-To: <200301202258.WAA02263@rudolph.ccur.com> References: <200301202258.WAA02263@rudolph.ccur.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Organization: Message-Id: <1043119361.13344.11.camel@dhcp22.swansea.linux.org.uk> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.1 (1.2.1-2) Date: 21 Jan 2003 03:22:42 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2003-01-20 at 22:58, Joe Korty wrote: > The new, preemptable spin_lock() spins on an atomic bus-locking > read/write instead of an ordinary read, as the original spin_lock > implementation did. Perhaps that is the source of the inefficiency > being seen. Its a fairly critical "Never do this" on older intel processors and kills the box very efficiently so your diagnosis is extremely plausible - 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/