[1/3] scsi_debug: Increase the reported optimal transfer length
diff mbox

Message ID 1450306433-20166-1-git-send-email-martin.petersen@oracle.com
State New
Headers show

Commit Message

Martin K. Petersen Dec. 16, 2015, 10:53 p.m. UTC
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 <martin.petersen@oracle.com>
---
 drivers/scsi/scsi_debug.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Douglas Gilbert Dec. 16, 2015, 11:14 p.m. UTC | #1
On 15-12-16 05:53 PM, 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 <martin.petersen@oracle.com>

Acked-by: Douglas Gilbert <dgilbert@interlog.com>

> ---
>   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])");
>

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Ewan D. Milne Dec. 17, 2015, 1:18 p.m. UTC | #2
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 <martin.petersen@oracle.com>
> ---
>  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 <emilne@redhat.com>


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Patch
diff mbox

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])");