It is observed on null_blk that IOPS can be improved much by simply making
hw queue per NUMA node, so this patch applies the introduced .host_tagset
for improving performance.
In reality, .can_queue is quite big, and NUMA node number is often small, so
each hw queue's depth should be high enough to saturate device.
Cc: Arun Easi <arun.e...@cavium.com>
Cc: Omar Sandoval <osan...@fb.com>,
Cc: "Martin K. Petersen" <martin.peter...@oracle.com>,
Cc: James Bottomley <james.bottom...@hansenpartnership.com>,
Cc: Christoph Hellwig <h...@lst.de>,
Cc: Don Brace <don.br...@microsemi.com>
Cc: Kashyap Desai <kashyap.de...@broadcom.com>
Cc: Peter Rivera <peter.riv...@broadcom.com>
Cc: Laurence Oberman <lober...@redhat.com>
Cc: Hannes Reinecke <h...@suse.de>
Cc: Mike Snitzer <snit...@redhat.com>
Signed-off-by: Ming Lei <ming....@redhat.com>
---
drivers/scsi/megaraid/megaraid_sas_base.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c
b/drivers/scsi/megaraid/megaraid_sas_base.c
index 065956cb2aeb..0b46f97cbfdb 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -3177,6 +3177,7 @@ static struct scsi_host_template megasas_template = {
.use_clustering = ENABLE_CLUSTERING,
.change_queue_depth = scsi_change_queue_depth,
.no_write_same = 1,
+ .host_tagset = 1,
};
/**
@@ -5947,6 +5948,8 @@ static int megasas_start_aen(struct megasas_instance
*instance)
static int megasas_io_attach(struct megasas_instance *instance)
{
struct Scsi_Host *host = instance->host;
+ /* 256 tags should be high enough to saturate device */
+ int max_queues = DIV_ROUND_UP(host->can_queue, 256);
/*
* Export parameters required by SCSI mid-layer
@@ -5987,6 +5990,9 @@ static int megasas_io_attach(struct megasas_instance
*instance)
host->max_lun = MEGASAS_MAX_LUN;
host->max_cmd_len = 16;
+ /* per NUMA node hw queue */
+ host->nr_hw_queues = min_t(int, nr_node_ids, max_queues);
+
/*
* Notify the mid-layer about the new controller
*/
--
2.9.5
