From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48084) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoOYX-00055a-AO for qemu-devel@nongnu.org; Tue, 11 Nov 2014 22:25:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoOYR-0006ku-3m for qemu-devel@nongnu.org; Tue, 11 Nov 2014 22:25:17 -0500 Received: from mail-pa0-f48.google.com ([209.85.220.48]:39202) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoOYQ-0006kp-Ut for qemu-devel@nongnu.org; Tue, 11 Nov 2014 22:25:11 -0500 Received: by mail-pa0-f48.google.com with SMTP id ey11so11922671pad.7 for ; Tue, 11 Nov 2014 19:25:10 -0800 (PST) From: Ming Lei Date: Wed, 12 Nov 2014 11:24:35 +0800 Message-Id: <1415762675-11237-1-git-send-email-ming.lei@canonical.com> Subject: [Qemu-devel] [PATCH] virtio-scsi: dataplane: suppress guest notification List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, 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 Signed-off-by: Ming Lei --- 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