* [Qemu-devel] [PATCH] virtio-scsi: dataplane: suppress guest notification
@ 2014-11-12 3:24 Ming Lei
2014-11-12 10:19 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: Ming Lei @ 2014-11-12 3:24 UTC (permalink / raw)
To: qemu-devel, Paolo Bonzini, Stefan Hajnoczi, Kevin Wolf
Cc: Ming Lei, Fam Zheng, Anthony Liguori, Michael S. Tsirkin
This patch uses vring_should_notify() to suppress
guest notification, and looks notification frequency
can be decreased from ~33K/sec to ~2K/sec in my test
environment.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
hw/scsi/virtio-scsi-dataplane.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index df17229..be3b042 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -93,9 +93,14 @@ VirtIOSCSIReq *virtio_scsi_pop_req_vring(VirtIOSCSI *s,
void virtio_scsi_vring_push_notify(VirtIOSCSIReq *req)
{
+ VirtIODevice *vdev = VIRTIO_DEVICE(req->vring->parent);
+
vring_push(&req->vring->vring, &req->elem,
req->qsgl.size + req->resp_iov.size);
- event_notifier_set(&req->vring->guest_notifier);
+
+ if (vring_should_notify(vdev, &req->vring->vring)) {
+ event_notifier_set(&req->vring->guest_notifier);
+ }
}
static void virtio_scsi_iothread_handle_ctrl(EventNotifier *notifier)
--
1.7.9.5
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [Qemu-devel] [PATCH] virtio-scsi: dataplane: suppress guest notification
2014-11-12 3:24 [Qemu-devel] [PATCH] virtio-scsi: dataplane: suppress guest notification Ming Lei
@ 2014-11-12 10:19 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2014-11-12 10:19 UTC (permalink / raw)
To: Ming Lei, qemu-devel, Stefan Hajnoczi, Kevin Wolf
Cc: Fam Zheng, Anthony Liguori, Michael S. Tsirkin
On 12/11/2014 04:24, Ming Lei wrote:
> This patch uses vring_should_notify() to suppress
> guest notification, and looks notification frequency
> can be decreased from ~33K/sec to ~2K/sec in my test
> environment.
>
> Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Ming Lei <ming.lei@canonical.com>
> ---
> hw/scsi/virtio-scsi-dataplane.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
> index df17229..be3b042 100644
> --- a/hw/scsi/virtio-scsi-dataplane.c
> +++ b/hw/scsi/virtio-scsi-dataplane.c
> @@ -93,9 +93,14 @@ VirtIOSCSIReq *virtio_scsi_pop_req_vring(VirtIOSCSI *s,
>
> void virtio_scsi_vring_push_notify(VirtIOSCSIReq *req)
> {
> + VirtIODevice *vdev = VIRTIO_DEVICE(req->vring->parent);
> +
> vring_push(&req->vring->vring, &req->elem,
> req->qsgl.size + req->resp_iov.size);
> - event_notifier_set(&req->vring->guest_notifier);
> +
> + if (vring_should_notify(vdev, &req->vring->vring)) {
> + event_notifier_set(&req->vring->guest_notifier);
> + }
> }
>
> static void virtio_scsi_iothread_handle_ctrl(EventNotifier *notifier)
>
Thanks, applied.
Paolo
^ permalink raw reply [flat|nested] 2+ messages in thread
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