diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2012-01-12 09:14:42 +0400 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2012-01-12 09:14:42 +0400 |
| commit | 7b21e34fd1c272e3a8c3846168f2f6287a4cd72b (patch) | |
| tree | 0f94c9f834f5b7cd8ba87168df892ed17b09cb8f /drivers/virtio/virtio_mmio.c | |
| parent | e343a895a9f342f239c5e3c5ffc6c0b1707e6244 (diff) | |
| download | linux-7b21e34fd1c272e3a8c3846168f2f6287a4cd72b.tar.xz | |
virtio: harsher barriers for rpmsg.
We were cheating with our barriers; using the smp ones rather than the
real device ones. That was fine, until rpmsg came along, which is
used to talk to a real device (a non-SMP CPU).
Unfortunately, just putting back the real barriers (reverting
d57ed95d) causes a performance regression on virtio-pci. In
particular, Amos reports netbench's TCP_RR over virtio_net CPU
utilization increased up to 35% while throughput went down by up to
14%.
By comparison, this branch is in the noise.
Reference: https://lkml.org/lkml/2011/12/11/22
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/virtio/virtio_mmio.c')
| -rw-r--r-- | drivers/virtio/virtio_mmio.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 0269717436af..01d6dc250d5c 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -310,8 +310,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); /* Create the vring */ - vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, - vdev, info->queue, vm_notify, callback, name); + vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, vdev, + true, info->queue, vm_notify, callback, name); if (!vq) { err = -ENOMEM; goto error_new_virtqueue; |