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| author | Michael S. Tsirkin <mst@redhat.com> | 2012-11-30 00:02:56 +0200 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2012-11-29 17:25:02 -0600 |
| commit | e1f7b4812eab992de46c98b3726745afb042a7f0 (patch) | |
| tree | 288ec43f0807224674026579208dc46748bcaf32 /hw/virtio-serial-bus.c | |
| parent | 044d003db9b6a588be2c9d0ec9de694ba3848551 (diff) | |
| download | focaccia-qemu-e1f7b4812eab992de46c98b3726745afb042a7f0.tar.gz focaccia-qemu-e1f7b4812eab992de46c98b3726745afb042a7f0.zip | |
virtio: limit avail bytes lookahead
Commit 0d8d7690850eb0cf2b2b60933cf47669a6b6f18f introduced a regression in virtio-net performance because it looks into the ring aggressively while we really only care about a single packet worth of buffers. Reported as bugzilla 1066055 in launchpad. To fix, add parameters limiting lookahead, and use in virtqueue_avail_bytes. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reported-by: Edivaldo de Araujo Pereira <edivaldoapereira@yahoo.com.br> Tested-by: Edivaldo de Araujo Pereira <edivaldoapereira@yahoo.com.br> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'hw/virtio-serial-bus.c')
| -rw-r--r-- | hw/virtio-serial-bus.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c index efa8a81db6..155da58dcd 100644 --- a/hw/virtio-serial-bus.c +++ b/hw/virtio-serial-bus.c @@ -306,7 +306,7 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port) if (use_multiport(port->vser) && !port->guest_connected) { return 0; } - virtqueue_get_avail_bytes(vq, &bytes, NULL); + virtqueue_get_avail_bytes(vq, &bytes, NULL, 4096, 0); return bytes; } |