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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 /include/linux/virtio_ring.h | |
| parent | e343a895a9f342f239c5e3c5ffc6c0b1707e6244 (diff) | |
| download | linux-7b21e34fd1c272e3a8c3846168f2f6287a4cd72b.tar.gz linux-7b21e34fd1c272e3a8c3846168f2f6287a4cd72b.tar.bz2 linux-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 'include/linux/virtio_ring.h')
| -rw-r--r-- | include/linux/virtio_ring.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index 36be0f6e18a9..e338730c2660 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -168,6 +168,7 @@ struct virtqueue; struct virtqueue *vring_new_virtqueue(unsigned int num, unsigned int vring_align, struct virtio_device *vdev, + bool weak_barriers, void *pages, void (*notify)(struct virtqueue *vq), void (*callback)(struct virtqueue *vq), |