From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: [PATCH] [29/82] x86_64: Rename IOMMU option, fix help and mark option embedded. Date: Sun, 25 Jun 2006 18:21:15 -0400 Message-ID: <20060625222115.GA17213@devserv.devel.redhat.com> References: <449C852C.mailCZT11F9YB@suse.de> <200606251722.23294.ak@suse.de> <20060625190054.GA6570@devserv.devel.redhat.com> <200606252132.41121.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([66.187.233.31]:28381 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S932398AbWFYWVd (ORCPT ); Sun, 25 Jun 2006 18:21:33 -0400 Content-Disposition: inline In-Reply-To: <200606252132.41121.ak@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Andi Kleen Cc: Alan Cox , torvalds@osdl.org, discuss@x86-64.org, akpm@osdl.org, markh@osdl.org, linux-scsi@vger.kernel.org, axboe@suse.de On Sun, Jun 25, 2006 at 09:32:41PM +0200, Andi Kleen wrote: > > From a tiny 16MB DMA pool that can't sustain the required load ? Or has that > > bit changed. > > It should be ok because it blocks. It will be slow, but what else do you expect > from broken hardware like this? Sustained 80Mbyte/second I/O rates. At least thats what it gets in other OS products. This is one of the reasons (broadcomm 4400 was another) that a 30 or 31 bit DMA zone not a 32bit one was called for, which also didn't happen it seems. The ifdef approach isnt perfect but it essentially means you get good performance on x86-32 and only x86-64 has problems which seems fine to me, because its an old card. Alan