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@xxxxxxxxxx> --- drivers/vhost/scsi.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 2c3cf487cc71..c83f7f043470 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -1927,6 +1927,14 @@ vhost_scsi_ioctl(struct file *f, if (copy_from_user(&features, featurep, sizeof features)) return -EFAULT; return vhost_scsi_set_features(vs, features); + case VHOST_NEW_WORKER: + case VHOST_FREE_WORKER: + case VHOST_ATTACH_VRING_WORKER: + case VHOST_GET_VRING_WORKER: + mutex_lock(&vs->dev.mutex); + r = vhost_worker_ioctl(&vs->dev, ioctl, argp); + mutex_unlock(&vs->dev.mutex); + return r; default: mutex_lock(&vs->dev.mutex); r = vhost_dev_ioctl(&vs->dev, ioctl, argp); -- 2.25.1 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
