| commit | faf1e1fb4cdd3f1f71c948cb53e7d50f0798a202 | |
| author | Fam Zheng <famz@redhat.com> | |
| Tue, 16 Sep 2014 07:20:18 +0000 (16 15:20 +0800) | ||
| committer | Paolo Bonzini <pbonzini@redhat.com> | |
| Tue, 23 Sep 2014 13:40:51 +0000 (23 15:40 +0200) | ||
| tree | f2e3147381d466782ceca7eabb81664309a073b5 | treesnapshot (tar.gz zip) |
| parent | 61e68b3fbd3e2b7beb636bc56f78d9c1ca25e8f9 | commitdiff |
virtio-scsi: Optimize virtio_scsi_init_req
The VirtQueueElement is a very big structure (>48k!), since it will be
initialzed by virtqueue_pop, we can save the expensive zeroing here.
This saves a few microseconds per request in my test:
[fio-test] rw bs iodepth jobs bw iops latency
--------------------------------------------------------------------------------------------
Before read 4k 1 1 110 28269 34
After read 4k 1 1 131 33745 28
Whereas,
virtio-blk read 4k 1 1 217 55673 16
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The VirtQueueElement is a very big structure (>48k!), since it will be
initialzed by virtqueue_pop, we can save the expensive zeroing here.
This saves a few microseconds per request in my test:
[fio-test] rw bs iodepth jobs bw iops latency
--------------------------------------------------------------------------------------------
Before read 4k 1 1 110 28269 34
After read 4k 1 1 131 33745 28
Whereas,
virtio-blk read 4k 1 1 217 55673 16
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| hw/scsi/virtio-scsi.c | diffblobblamehistory |