vhost_scsi: add support for worker ioctls
This has vhost-scsi support the worker ioctls by calling the
vhost_worker_ioctl helper.
With a single worker, the single thread becomes a bottlneck when trying
to use 3 or more virtqueues like:
fio --filename=/dev/sdb --direct=1 --rw=randrw --bs=4k \
--ioengine=libaio --iodepth=128 --numjobs=3
With the patches and doing a worker per vq, we can scale to at least
16 vCPUs/vqs (that's my system limit) with the same command fio command
above with numjobs=16:
fio --filename=/dev/sdb --direct=1 --rw=randrw --bs=4k \
--ioengine=libaio --iodepth=64 --numjobs=16
which gives around 2002K IOPs.
Note that for testing I dropped depth to 64 above because the vhost/virt
layer supports only 1024 total commands per device. And the only tuning I
did was set LIO's emulate_pr to 0 to avoid LIO's PR lock in the main IO
path which becomes an issue at around 12 jobs/virtqueues.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20230626232307.97930-17-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
1 file changed
