From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57468) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZZvX-0001u8-Oq for qemu-devel@nongnu.org; Thu, 11 Jan 2018 05:17:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eZZvS-0001AS-RI for qemu-devel@nongnu.org; Thu, 11 Jan 2018 05:17:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47464) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eZZvS-00017B-KD for qemu-devel@nongnu.org; Thu, 11 Jan 2018 05:17:34 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0CC018763C for ; Thu, 11 Jan 2018 10:17:23 +0000 (UTC) From: Gal Hammer Date: Thu, 11 Jan 2018 12:16:56 +0200 Message-Id: <1515665816-10313-1-git-send-email-ghammer@redhat.com> Subject: [Qemu-devel] [PATCH] virtio: improve virtio devices initialization time List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: mst@redhat.com, Gal Hammer The loading time of a VM is quite significant when its virtio devices uses 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 --- hw/virtio/virtio.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index ad564b0..8d8d93d 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]; @@ -2632,6 +2636,13 @@ static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) continue; } event_notifier_set_handler(&vq->host_notifier, NULL); + } + memory_region_transaction_commit(); + + for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { + if (!virtio_queue_get_num(vdev, n)) { + continue; + } r = virtio_bus_set_host_notifier(qbus, n, false); assert(r >= 0); } -- 2.7.5