Re: [PATCH] virtio_blk: set the default scheduler to none

[Ming Lei]

On Thu, Dec 07, 2023 at 12:31:05PM +0800, Li Feng wrote:
> virtio-blk is generally used in cloud computing scenarios, where the
> performance of virtual disks is very important. The mq-deadline scheduler
> has a big performance drop compared to none with single queue. In my tests,
> mq-deadline 4k readread iops were 270k compared to 450k for none. So here
> the default scheduler of virtio-blk is set to "none".

The test result shows you may not test HDD. backing of virtio-blk.

none can lose IO merge capability more or less, so probably sequential IO perf
drops in case of HDD backing.

Thanks,
Ming