-
由 Jason Wang 提交于
When event index was enabled, we need to fetch used event from userspace memory each time. This userspace fetch (with memory barrier) could be saved sometime when 1) caching used event and 2) if used event is ahead of new and old to new updating does not cross it, we're sure there's no need to notify guest. This will be useful for heavy tx load e.g guest pktgen test with Linux driver shows ~3.5% improvement. Signed-off-by: NJason Wang <jasowang@redhat.com> Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
809ecb9b