From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262605AbUEGDCe (ORCPT ); Thu, 6 May 2004 23:02:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262719AbUEGDCe (ORCPT ); Thu, 6 May 2004 23:02:34 -0400 Received: from fw.osdl.org ([65.172.181.6]:24200 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S262605AbUEGDCd (ORCPT ); Thu, 6 May 2004 23:02:33 -0400 Date: Thu, 6 May 2004 20:02:10 -0700 From: Andrew Morton To: "Chen, Kenneth W" Cc: axboe@suse.de, linux-kernel@vger.kernel.org Subject: Re: Cache queue_congestion_on/off_threshold Message-Id: <20040506200210.44b04c38.akpm@osdl.org> In-Reply-To: <200405062030.i46KUuF13625@unix-os.sc.intel.com> References: <20040506064301.GC10069@suse.de> <200405062030.i46KUuF13625@unix-os.sc.intel.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "Chen, Kenneth W" wrote: > > >>>> Jens Axboe wrote on Wed, May 05, 2004 11:43 PM > > On Wed, May 05 2004, Andrew Morton wrote: > > > Jens Axboe wrote: > > > > > > > > Do you have any numbers at all for this? I'd say these calculations are > > > > severly into the noise area when submitting io. > > > > > > The difference will not be measurable, but I think the patch makes sense > > > regardless of what the numbers say. > > > > Humm dunno, I'd rather save the sizeof(int) * 2. > > Strictly speaking from memory consumption point of view, it probably comes > for free since sizeof(struct request_queue) currently is 456 bytes on x86 > and 816 on 64bit arch. The structure is being rounded to 512 or 1024 with > kmalloc. That's a good argument for creating a standalone slab cache for request queue structures ;)