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| author | Denis Plotnikov <dplotnikov@virtuozzo.com> | 2020-02-14 10:46:48 +0300 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2020-02-22 08:26:47 +0000 |
| commit | c9b7d9ec21dfca716f0bb3b68dee75660d86629c (patch) | |
| tree | a1dd32e40939607157457ed2dec0d16f5e4ff295 /hw/block | |
| parent | 9ac5df20f51fabcba0d902025df4bd7ea987c158 (diff) | |
| download | qemu-c9b7d9ec21dfca716f0bb3b68dee75660d86629c.zip qemu-c9b7d9ec21dfca716f0bb3b68dee75660d86629c.tar.gz qemu-c9b7d9ec21dfca716f0bb3b68dee75660d86629c.tar.bz2 | |
virtio: increase virtqueue size for virtio-scsi and virtio-blk
The goal is to reduce the amount of requests issued by a guest on
1M reads/writes. This rises the performance up to 4% on that kind of
disk access pattern.
The maximum chunk size to be used for the guest disk accessing is
limited with seg_max parameter, which represents the max amount of
pices in the scatter-geather list in one guest disk request.
Since seg_max is virqueue_size dependent, increasing the virtqueue
size increases seg_max, which, in turn, increases the maximum size
of data to be read/write from a guest disk.
More details in the original problem statment:
https://lists.gnu.org/archive/html/qemu-devel/2017-12/msg03721.html
Suggested-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
Message-id: 20200214074648.958-1-dplotnikov@virtuozzo.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'hw/block')
| -rw-r--r-- | hw/block/virtio-blk.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 09f46ed..142863a 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1272,7 +1272,7 @@ static Property virtio_blk_properties[] = { DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0, true), DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, 1), - DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 128), + DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 256), DEFINE_PROP_BOOL("seg-max-adjust", VirtIOBlock, conf.seg_max_adjust, true), DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD, IOThread *), |