Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933308Ab3HNV1L (ORCPT ); Wed, 14 Aug 2013 17:27:11 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:34636 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933121Ab3HNV1J (ORCPT ); Wed, 14 Aug 2013 17:27:09 -0400 Message-ID: <1376515627.2028.41.camel@dabdike.int.hansenpartnership.com> Subject: Re: [PATCH 1/1] cciss: set max scatter gather entries to 32 on P600 From: James Bottomley To: mike.miller@hp.com, mikem@thumper.usa.hp.com Cc: Andrew Morton , Jens Axboe , LKML-scsi , LKML , thenzl@redhat.com, bubrown@redhat.com, scameron@beardog.cce.hp.com Date: Wed, 14 Aug 2013 14:27:07 -0700 In-Reply-To: <20130814205236.GB23042@beardog.cce.hp.com> References: <20130814205236.GB23042@beardog.cce.hp.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.8.3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1283 Lines: 32 On Wed, 2013-08-14 at 15:52 -0500, Mike Miller wrote: > Patch 1/1 > > From: Mike Miller > > At one time we used to set the maximum number of scatter gather elements on > all Smart Array controllers to 32. At some point in time the firmware began > to write the "appropriate" value for each controller into the config table. > The cciss driver would then read that and set h->maxsgentries. > > h->maxsgentries = readl(&(h->cfgtable->MaxSGElements); > > On the P600 that value is 544. Under some workloads a significant > performance reduction may result. This patch forces the P600 to use only 32 > scatter gather elements. Other controllers are not affected. > > Signed-off-by: Mike Miller > Signed-off-by: Dwight (Bud) Brown > Signed-off-by: Tomas Henzl > Acked-by: Stephen M. Cameron I don't quite understand the signoff chain on this patch. For a one line patch, are you saying it has three authors? James -- 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/