From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46406) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ecH3Q-0003RR-JD for qemu-devel@nongnu.org; Thu, 18 Jan 2018 15:44:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ecH3P-0003SN-80 for qemu-devel@nongnu.org; Thu, 18 Jan 2018 15:44:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60292) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ecH3P-0003Qt-22 for qemu-devel@nongnu.org; Thu, 18 Jan 2018 15:44:55 -0500 Date: Thu, 18 Jan 2018 22:44:52 +0200 From: "Michael S. Tsirkin" Message-ID: <1516308132-10272-9-git-send-email-mst@redhat.com> References: <1516308132-10272-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1516308132-10272-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL v4 08/29] virtio: improve virtio devices initialization time List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Gal Hammer , Sitong Liu , Xiaoling Gao From: Gal Hammer The loading time of a VM is quite significant when its virtio devices use a large amount of virt-queues (e.g. a virtio-serial device with max_ports=511). Most of the time is spend in the creation of all the required event notifiers (ioeventfd and memory regions). This patch pack all the changes to the memory regions in a single memory transaction. Reported-by: Sitong Liu Reported-by: Xiaoling Gao Signed-off-by: Gal Hammer Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index d6002ee..3ac3491 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2574,6 +2574,7 @@ static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev) VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); int n, r, err; + memory_region_transaction_begin(); for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { VirtQueue *vq = &vdev->vq[n]; if (!virtio_queue_get_num(vdev, n)) { @@ -2596,6 +2597,7 @@ static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev) } event_notifier_set(&vq->host_notifier); } + memory_region_transaction_commit(); return 0; assign_error: @@ -2609,6 +2611,7 @@ assign_error: r = virtio_bus_set_host_notifier(qbus, n, false); assert(r >= 0); } + memory_region_transaction_commit(); return err; } @@ -2625,6 +2628,7 @@ static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); int n, r; + memory_region_transaction_begin(); for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { VirtQueue *vq = &vdev->vq[n]; @@ -2635,6 +2639,7 @@ static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) r = virtio_bus_set_host_notifier(qbus, n, false); assert(r >= 0); } + memory_region_transaction_commit(); } void virtio_device_stop_ioeventfd(VirtIODevice *vdev) -- MST