diff options
| author | Peter Lieven <pl@kamp.de> | 2015-02-02 14:52:21 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2015-02-06 17:24:21 +0100 |
| commit | 95f7142abc86a916682bd735aecd90172ffa0d30 (patch) | |
| tree | d491d0f48d2f6b645383fa6d314264d861780dd8 /hw/block/dataplane | |
| parent | 454057b7d9b9ad141bd5df8c4075745e56b4870f (diff) | |
| download | qemu-95f7142abc86a916682bd735aecd90172ffa0d30.zip | |
virtio-blk: introduce multiread
this patch finally introduces multiread support to virtio-blk. While
multiwrite support was there for a long time, read support was missing.
The complete merge logic is moved into virtio-blk.c which has
been the only user of request merging ever since. This is required
to be able to merge chunks of requests and immediately invoke callbacks
for those requests. Secondly, this is required to switch to
direct invocation of coroutines which is planned at a later stage.
The following benchmarks show the performance of running fio with
4 worker threads on a local ram disk. The numbers show the average
of 10 test runs after 1 run as warmup phase.
| 4k | 64k | 4k
MB/s | rd seq | rd rand | rd seq | rd rand | wr seq | wr rand
--------------+--------+---------+--------+---------+--------+--------
master | 1221 | 1187 | 4178 | 4114 | 1745 | 1213
multiread | 1829 | 1189 | 4639 | 4110 | 1894 | 1216
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'hw/block/dataplane')
| -rw-r--r-- | hw/block/dataplane/virtio-blk.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index 39c5d7103c..be957d1117 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -96,9 +96,7 @@ static void handle_notify(EventNotifier *e) event_notifier_test_and_clear(&s->host_notifier); blk_io_plug(s->conf->conf.blk); for (;;) { - MultiReqBuffer mrb = { - .num_writes = 0, - }; + MultiReqBuffer mrb = {}; int ret; /* Disable guest->host notifies to avoid unnecessary vmexits */ @@ -120,7 +118,9 @@ static void handle_notify(EventNotifier *e) virtio_blk_handle_request(req, &mrb); } - virtio_submit_multiwrite(s->conf->conf.blk, &mrb); + if (mrb.num_reqs) { + virtio_blk_submit_multireq(s->conf->conf.blk, &mrb); + } if (likely(ret == -EAGAIN)) { /* vring emptied */ /* Re-enable guest->host notifies and stop processing the vring. |