]> git.baikalelectronics.ru Git - kernel.git/commit
scsi: storvsc: Correctly set number of hardware queues for IDE disk
authorLong Li <longli@microsoft.com>
Tue, 14 Jan 2020 00:08:36 +0000 (16:08 -0800)
committerMartin K. Petersen <martin.petersen@oracle.com>
Thu, 16 Jan 2020 04:02:24 +0000 (23:02 -0500)
commit8888c5f81b960b78f6824c10405613491a6e22ec
treefb61a98dda7889e07c6641f02792019275f9b04a
parent468256728e35f670d811bdd281ce2964373e773a
scsi: storvsc: Correctly set number of hardware queues for IDE disk

Commit c56bf26141d2 ("scsi: storvsc: setup 1:1 mapping between hardware
queue and CPU queue") introduced a regression for disks attached to
IDE. For these disks the host VSP only offers one VMBUS channel. Setting
multiple queues can overload the VMBUS channel and result in performance
drop for high queue depth workload on system with large number of CPUs.

Fix it by leaving the number of hardware queues to 1 (default value) for
IDE disks.

Fixes: c56bf26141d2 ("scsi: storvsc: setup 1:1 mapping between hardware queue and CPU queue")
Link: https://lore.kernel.org/r/1578960516-108228-1-git-send-email-longli@linuxonhyperv.com
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
drivers/scsi/storvsc_drv.c