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authorPeter Lieven <pl@kamp.de>2015-02-02 14:52:21 +0100
committerKevin Wolf <kwolf@redhat.com>2015-02-06 17:24:21 +0100
commit95f7142abc86a916682bd735aecd90172ffa0d30 (patch)
treed491d0f48d2f6b645383fa6d314264d861780dd8 /hw/block/dataplane
parent454057b7d9b9ad141bd5df8c4075745e56b4870f (diff)
downloadhqemu-95f7142abc86a916682bd735aecd90172ffa0d30.zip
hqemu-95f7142abc86a916682bd735aecd90172ffa0d30.tar.gz
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.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 39c5d71..be957d1 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.
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