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| author | Paolo Bonzini | 2017-01-11 09:38:15 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin | 2017-01-18 21:59:53 +0100 |
| commit | 4a3f03ba8dbf53fce36d0c1dd5d0cc0f340fe5f3 (patch) | |
| tree | 73d33b70660c43ee052d97ecdfc02aecb4bfce36 /scripts | |
| parent | Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2017-01-16' into ... (diff) | |
| download | qemu-4a3f03ba8dbf53fce36d0c1dd5d0cc0f340fe5f3.tar.gz qemu-4a3f03ba8dbf53fce36d0c1dd5d0cc0f340fe5f3.tar.xz qemu-4a3f03ba8dbf53fce36d0c1dd5d0cc0f340fe5f3.zip | |
virtio-net: enable ioeventfd even if vhost=off
virtio-net-pci does not enable ioeventfd for historical reasons (and
nobody ever checked whether it should be revisited). Note that other
backends do enable ioeventfd for virtio-net.
However, it has a major effect on performance. On Windows, throughput is
_multiplied_ by 2 or 3 on TCP_STREAM (on small packets it is "only" a 30%
improvement) and a little less so on TCP_MAERTS albeit still very much
statistically significant. Latency also has a single digit improvement.
This is not visible when using vhost, which forces ioeventfd=on, but it
is substantial without vhost. In addition, also on Windows and with the
RHEL 7.3 kernel, APICv seems to slow down virtio-net performance a bit,
but the penalty with this patch goes from -25% to -7%.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'scripts')
0 files changed, 0 insertions, 0 deletions