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| author |   Rusty Russell <rusty@rustcorp.com.au> | 2012-01-12 15:44:42 +1030 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2012-01-12 15:44:42 +1030 |
| commit | 7b21e34fd1c272e3a8c3846168f2f6287a4cd72b (patch) | |
| tree | 0f94c9f834f5b7cd8ba87168df892ed17b09cb8f /drivers/virtio/virtio_pci.c | |
| parent | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost (diff) | |
| download | linux-dev-7b21e34fd1c272e3a8c3846168f2f6287a4cd72b.tar.xz linux-dev-7b21e34fd1c272e3a8c3846168f2f6287a4cd72b.zip | |
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_pci.c')
| -rw-r--r-- | drivers/virtio/virtio_pci.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index baabb7937ec2..688b42d28dad 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -414,8 +414,8 @@ static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN); /* create the vring */ - vq = vring_new_virtqueue(info->num, VIRTIO_PCI_VRING_ALIGN, - vdev, info->queue, vp_notify, callback, name); + vq = vring_new_virtqueue(info->num, VIRTIO_PCI_VRING_ALIGN, vdev, + true, info->queue, vp_notify, callback, name); if (!vq) { err = -ENOMEM; goto out_activate_queue; |