Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754805AbYGXP3J (ORCPT ); Thu, 24 Jul 2008 11:29:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753113AbYGXP2y (ORCPT ); Thu, 24 Jul 2008 11:28:54 -0400 Received: from accolon.hansenpartnership.com ([76.243.235.52]:43183 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752662AbYGXP2w (ORCPT ); Thu, 24 Jul 2008 11:28:52 -0400 Subject: Re: [PATCH] block: fix q->max_segment_size checking in blk_recalc_rq_segments about VMERGE From: James Bottomley To: Mikulas Patocka Cc: David Miller , fujita.tomonori@lab.ntt.co.jp, jens.axboe@oracle.com, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-parisc@vger.kernel.org In-Reply-To: References: <1216520228.3376.33.camel@localhost.localdomain> <20080719.210737.197246608.davem@davemloft.net> <1216565545.4199.10.camel@localhost.localdomain> <20080720.102302.137955996.davem@davemloft.net> <1216575211.4199.35.camel@localhost.localdomain> Content-Type: text/plain Date: Thu, 24 Jul 2008 11:28:34 -0400 Message-Id: <1216913314.4524.25.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 (2.22.3.1-1.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 950 Lines: 23 On Thu, 2008-07-24 at 11:07 -0400, Mikulas Patocka wrote: > So try to #define BIO_VMERGE_BOUNDARY 0 for Pa-Risc and tell us what > performance degradation do you see (and what driver do you use and what is > the I/O pattern). > > If you show something specific, we can consider that --- but you haven't > yet told us anything, except generic talk. You keep ignoring inconvenient facts. For about the third time: I run a test bed for sg_tables (large chaining of requests). This runs on parisc using virtual merging (has to because the final physical table size can't go over the sg list of the SCSI card). If I turn off virtual merging I can no longer test sg_tables in vanilla kernels. 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/