From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262956AbUEGJfQ (ORCPT ); Fri, 7 May 2004 05:35:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263163AbUEGJfQ (ORCPT ); Fri, 7 May 2004 05:35:16 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:23238 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S262956AbUEGJfK (ORCPT ); Fri, 7 May 2004 05:35:10 -0400 Date: Fri, 7 May 2004 11:35:03 +0200 From: Jens Axboe To: Andrew Morton Cc: "Chen, Kenneth W" , linux-kernel@vger.kernel.org Subject: Re: Cache queue_congestion_on/off_threshold Message-ID: <20040507093503.GC21109@suse.de> References: <20040506064301.GC10069@suse.de> <200405062030.i46KUuF13625@unix-os.sc.intel.com> <20040506200210.44b04c38.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040506200210.44b04c38.akpm@osdl.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 06 2004, Andrew Morton wrote: > "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 ;) Precisely, it's definitely not a good argument to keep loading it. I'll do that. -- Jens Axboe