Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 1 Mar 2002 18:08:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 1 Mar 2002 18:08:33 -0500 Received: from vger.timpanogas.org ([207.109.151.240]:42393 "EHLO vger.timpanogas.org") by vger.kernel.org with ESMTP id ; Fri, 1 Mar 2002 18:07:58 -0500 Date: Fri, 1 Mar 2002 16:22:02 -0700 From: "Jeff V. Merkey" To: Alan Cox Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: queue_nr_requests needs to be selective Message-ID: <20020301162202.B12413@vger.timpanogas.org> In-Reply-To: <3C7FE7DD.98121E87@zip.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from alan@lxorguk.ukuu.org.uk on Fri, Mar 01, 2002 at 09:03:22PM +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 01, 2002 at 09:03:22PM +0000, Alan Cox wrote: > > I don't immediately see why increasing the queue length should > > increase bandwidth in this manner. One possibility is that > > Latency on the controllers ? With caches on the controller and disks you > can have a lot of requests actually in flight Since 3ware uses a switched architecture, there are a lot of requests in flight. Can we get the default value increased or alternately, allow RAID drivers to submit a local queue_nr_request value per adapter so for those cards with 8 drives that make themselves look like a single drive to Linux, sufficient buffers are available to prevent threads feeding the device from going to sleep all the time? :-) Jeff - 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/