On 12/4/20 3:26 PM, Brian King wrote:
On 12/2/20 11:27 AM, Tyrel Datwyler wrote:
On 12/2/20 7:14 AM, Brian King wrote:
On 12/1/20 6:53 PM, Tyrel Datwyler wrote:
Introduce several new vhost fields for managing MQ state of the adapter
as well as initial defaults for MQ enablement.
Signed-off-by: Tyrel Datwyler <tyreld@xxxxxxxxxxxxx>
---
drivers/scsi/ibmvscsi/ibmvfc.c | 9 ++++++++-
drivers/scsi/ibmvscsi/ibmvfc.h | 13 +++++++++++--
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 42e4d35e0d35..f1d677a7423d 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -5161,12 +5161,13 @@ static int ibmvfc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
}
shost->transportt = ibmvfc_transport_template;
- shost->can_queue = max_requests;
+ shost->can_queue = (max_requests / IBMVFC_SCSI_HW_QUEUES);
This doesn't look right. can_queue is the SCSI host queue depth, not the MQ queue depth.
Our max_requests is the total number commands allowed across all queues. From
what I understand is can_queue is the total number of commands in flight allowed
for each hw queue.
/*
* In scsi-mq mode, the number of hardware queues supported by the LLD.
*
* Note: it is assumed that each hardware queue has a queue depth of
* can_queue. In other words, the total queue depth per host
* is nr_hw_queues * can_queue. However, for when host_tagset is set,
* the total queue depth is can_queue.
*/
We currently don't use the host wide shared tagset.
Ok. I missed that bit... In that case, since we allocate by default only 100
event structs. If we slice that across IBMVFC_SCSI_HW_QUEUES (16) queues, then
we end up with only about 6 commands that can be outstanding per queue,
which is going to really hurt performance... I'd suggest bumping up
IBMVFC_MAX_REQUESTS_DEFAULT from 100 to 1000 as a starting point.
Before doing that I'd rather use the host-wide shared tagset.
Increasing the number of requests will increase the memory footprint of
the driver (as each request will be statically allocated).
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
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