This is a note to let you know that I've just added the patch titled
cxlflash: Increase cmd_per_lun for better throughput
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cxlflash-increase-cmd_per_lun-for-better-throughput.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 83430833b4d4a9c9b23964babbeb1f36450f8136 Mon Sep 17 00:00:00 2001
From: "Manoj N. Kumar" <manoj@xxxxxxxxxxxxxxxxxx>
Date: Fri, 4 Mar 2016 15:55:20 -0600
Subject: cxlflash: Increase cmd_per_lun for better throughput
From: Manoj N. Kumar <manoj@xxxxxxxxxxxxxxxxxx>
commit 83430833b4d4a9c9b23964babbeb1f36450f8136 upstream.
With the current value of cmd_per_lun at 16, the throughput
over a single adapter is limited to around 150kIOPS.
Increase the value of cmd_per_lun to 256 to improve
throughput. With this change a single adapter is able to
attain close to the maximum throughput (380kIOPS).
Also change the number of RRQ entries that can be queued.
Signed-off-by: Manoj N. Kumar <manoj@xxxxxxxxxxxxxxxxxx>
Acked-by: Matthew R. Ochs <mrochs@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Uma Krishnan <ukrishn@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/cxlflash/common.h | 8 +++++---
drivers/scsi/cxlflash/main.c | 2 +-
2 files changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/scsi/cxlflash/common.h
+++ b/drivers/scsi/cxlflash/common.h
@@ -34,7 +34,6 @@ extern const struct file_operations cxlf
sectors
*/
-#define NUM_RRQ_ENTRY 16 /* for master issued cmds */
#define MAX_RHT_PER_CONTEXT (PAGE_SIZE / sizeof(struct sisl_rht_entry))
/* AFU command retry limit */
@@ -48,9 +47,12 @@ extern const struct file_operations cxlf
index derivation
*/
-#define CXLFLASH_MAX_CMDS 16
+#define CXLFLASH_MAX_CMDS 256
#define CXLFLASH_MAX_CMDS_PER_LUN CXLFLASH_MAX_CMDS
+/* RRQ for master issued cmds */
+#define NUM_RRQ_ENTRY CXLFLASH_MAX_CMDS
+
static inline void check_sizes(void)
{
@@ -149,7 +151,7 @@ struct afu_cmd {
struct afu {
/* Stuff requiring alignment go first. */
- u64 rrq_entry[NUM_RRQ_ENTRY]; /* 128B RRQ */
+ u64 rrq_entry[NUM_RRQ_ENTRY]; /* 2K RRQ */
/*
* Command & data for AFU commands.
*/
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -2305,7 +2305,7 @@ static struct scsi_host_template driver_
.eh_device_reset_handler = cxlflash_eh_device_reset_handler,
.eh_host_reset_handler = cxlflash_eh_host_reset_handler,
.change_queue_depth = cxlflash_change_queue_depth,
- .cmd_per_lun = 16,
+ .cmd_per_lun = CXLFLASH_MAX_CMDS_PER_LUN,
.can_queue = CXLFLASH_MAX_CMDS,
.this_id = -1,
.sg_tablesize = SG_NONE, /* No scatter gather support */
Patches currently in stable-queue which might be from manoj@xxxxxxxxxxxxxxxxxx are
queue-4.4/cxlflash-increase-cmd_per_lun-for-better-throughput.patch