[Qemu-devel] Re: [PATCH v5 0/4] virtio: Use ioeventfd for virtqueue notify

[Stefan Hajnoczi]

Here are my results on qemu-kvm.git:

ioeventfd=on
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.0.2
(192.168.0.2) port 0 AF_INET
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384    200    10.00    1203.44

ioeventfd=off
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.0.2
(192.168.0.2) port 0 AF_INET
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384    200    10.00    1677.96

This is a 30% degradation that wasn't visible on qemu.git.

Same host.  qemu-kvm.git with v5 patches based on
cb1983b8809d0e06a97384a40bad1194a32fc814.

Stefan