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Updating the event index has a memory barrier and causes more work on the other side to actually signal the event. It is unnecessary if a new buffer has already appeared on the ring, so poll once before doing the update. The effect of this on the 0.9 ring implementation is pretty much invisible, but on the new-style ring it provides a consistent 3% performance improvement. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> |
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| .. | ||
| main.c | ||
| main.h | ||
| Makefile | ||
| noring.c | ||
| ptr_ring.c | ||
| README | ||
| ring.c | ||
| run-on-all.sh | ||
| virtio_ring_0_9.c | ||
| virtio_ring_inorder.c | ||
| virtio_ring_poll.c | ||
Partial implementation of various ring layouts, useful to tune virtio design. Uses shared memory heavily. Typical use: # sh run-on-all.sh perf stat -r 10 --log-fd 1 -- ./ring