From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ewan Milne Subject: Re: [PATCH 1/3] scsi_debug: Increase the reported optimal transfer length Date: Thu, 17 Dec 2015 08:18:58 -0500 Message-ID: <1450358338.22151.0.camel@localhost.localdomain> References: <1450306433-20166-1-git-send-email-martin.petersen@oracle.com> Reply-To: emilne@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54739 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965081AbbLQNS7 (ORCPT ); Thu, 17 Dec 2015 08:18:59 -0500 In-Reply-To: <1450306433-20166-1-git-send-email-martin.petersen@oracle.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org, linux-block@vger.kernel.org On Wed, 2015-12-16 at 17:53 -0500, Martin K. Petersen wrote: > The OPTIMAL TRANSFER LENGTH reported by scsi_debug is 64 blocks which > translates to 32KB with the default logical block size. That's much > lower than what real storage devices typically report (256KB to 1MB). > > Bump the optimal transfer length to 1024 blocks. > > Signed-off-by: Martin K. Petersen > --- > drivers/scsi/scsi_debug.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c > index d09d60293c27..b80b037f2982 100644 > --- a/drivers/scsi/scsi_debug.c > +++ b/drivers/scsi/scsi_debug.c > @@ -129,7 +129,7 @@ static const char *scsi_debug_version_date = "20141022"; > #define DEF_NO_LUN_0 0 > #define DEF_NUM_PARTS 0 > #define DEF_OPTS 0 > -#define DEF_OPT_BLKS 64 > +#define DEF_OPT_BLKS 1024 > #define DEF_PHYSBLK_EXP 0 > #define DEF_PTYPE 0 > #define DEF_REMOVABLE false > @@ -4140,7 +4140,7 @@ MODULE_PARM_DESC(no_lun_0, "no LU number 0 (def=0 -> have lun 0)"); > MODULE_PARM_DESC(no_uld, "stop ULD (e.g. sd driver) attaching (def=0))"); > MODULE_PARM_DESC(num_parts, "number of partitions(def=0)"); > MODULE_PARM_DESC(num_tgts, "number of targets per host to simulate(def=1)"); > -MODULE_PARM_DESC(opt_blks, "optimal transfer length in block (def=64)"); > +MODULE_PARM_DESC(opt_blks, "optimal transfer length in blocks (def=1024)"); > MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... (def=0)"); > MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)"); > MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])"); Reviewed-by: Ewan D. Milne