diff options
| author | mst@redhat.com <mst@redhat.com> | 2011-02-01 22:13:42 +0200 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2011-02-01 16:50:44 -0600 |
| commit | 5430a28fe452907c9e1b2097e073bc1ea4b29f39 (patch) | |
| tree | 066db9fdbac5a5ddca922b5d282161e9b6141b0e /hw/virtio-net.c | |
| parent | f157ed202e51dc2492b201dc34ed28e89c973fb7 (diff) | |
| download | qemu-5430a28fe452907c9e1b2097e073bc1ea4b29f39.tar.gz | |
vhost: force vhost off for non-MSI guests
When MSI is off, each interrupt needs to be bounced through the io
thread when it's set/cleared, so vhost-net causes more context switches and
higher CPU utilization than userspace virtio which handles networking in
the same thread.
We'll need to fix this by adding level irq support in kvm irqfd,
for now disable vhost-net in these configurations.
Added a vhostforce flag to force vhost-net back on.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'hw/virtio-net.c')
| -rw-r--r-- | hw/virtio-net.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/hw/virtio-net.c b/hw/virtio-net.c index 161f11445f..671d952921 100644 --- a/hw/virtio-net.c +++ b/hw/virtio-net.c @@ -119,7 +119,11 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t status) return; } if (!n->vhost_started) { - int r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer), &n->vdev); + int r; + if (!vhost_net_query(tap_get_vhost_net(n->nic->nc.peer), &n->vdev)) { + return; + } + r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer), &n->vdev); if (r < 0) { error_report("unable to start vhost net: %d: " "falling back on userspace virtio", -r); |