Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765109AbXE2Lco (ORCPT ); Tue, 29 May 2007 07:32:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760387AbXE2Lcf (ORCPT ); Tue, 29 May 2007 07:32:35 -0400 Received: from gate.crashing.org ([63.228.1.57]:54993 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755010AbXE2Lce (ORCPT ); Tue, 29 May 2007 07:32:34 -0400 Subject: Re: [patch 6/7] ps3: ROM Storage Driver From: Benjamin Herrenschmidt To: Geert Uytterhoeven Cc: Christoph Hellwig , linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org In-Reply-To: References: <20070525083607.784351000@sonycom.com> <20070525083632.677742000@sonycom.com> <20070529104948.GC29351@lst.de> Content-Type: text/plain Date: Tue, 29 May 2007 21:31:59 +1000 Message-Id: <1180438319.19517.150.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 685 Lines: 20 On Tue, 2007-05-29 at 13:11 +0200, Geert Uytterhoeven wrote: > > This looks very inefficient. Just set sg_tablesize of your driver > > to 1 to avoid getting mutiple segments. > > The disadvantage of setting sg_tablesize = 1 is that the driver will > get small > requests (PAGE_SIZE) most of the time, which is very bad for > performance. And the joke is that not only the HW can do scatter & gather but you also have an iommu ... Ben. - 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/