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author | Suwan Kim <suwan.kim027@gmail.com> | 2022-04-06 18:32:07 +0300 |
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committer | Michael S. Tsirkin <mst@redhat.com> | 2022-05-31 19:44:23 +0300 |
commit | 0e9911fa768f32f30e5678512ea405d99a7a9fef (patch) | |
tree | b127965ab9fb34ccec01dc2bed63280c7d89c692 /drivers/virtio | |
parent | 4e0400525691d0e676dbe002641f9a61261f1e1b (diff) | |
download | linux-0e9911fa768f32f30e5678512ea405d99a7a9fef.tar.xz |
virtio-blk: support mq_ops->queue_rqs()
This patch supports mq_ops->queue_rqs() hook. It has an advantage of
batch submission to virtio-blk driver. It also helps polling I/O because
polling uses batched completion of block layer. Batch submission in
queue_rqs() can boost polling performance.
In queue_rqs(), it iterates plug->mq_list, collects requests that
belong to same HW queue until it encounters a request from other
HW queue or sees the end of the list.
Then, virtio-blk adds requests into virtqueue and kicks virtqueue
to submit requests.
If there is an error, it inserts error request to requeue_list and
passes it to ordinary block layer path.
For verification, I did fio test.
(io_uring, randread, direct=1, bs=4K, iodepth=64 numjobs=N)
I set 4 vcpu and 2 virtio-blk queues for VM and run fio test 5 times.
It shows about 2% improvement.
| numjobs=2 | numjobs=4
-----------------------------------------------------------
fio without queue_rqs() | 291K IOPS | 238K IOPS
-----------------------------------------------------------
fio with queue_rqs() | 295K IOPS | 243K IOPS
For polling I/O performance, I also did fio test as below.
(io_uring, hipri, randread, direct=1, bs=512, iodepth=64 numjobs=4)
I set 4 vcpu and 2 poll queues for VM.
It shows about 2% improvement in polling I/O.
| IOPS | avg latency
-----------------------------------------------------------
fio poll without queue_rqs() | 424K | 613.05 usec
-----------------------------------------------------------
fio poll with queue_rqs() | 435K | 601.01 usec
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Suwan Kim <suwan.kim027@gmail.com>
Message-Id: <20220406153207.163134-3-suwan.kim027@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Diffstat (limited to 'drivers/virtio')
0 files changed, 0 insertions, 0 deletions