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

Chaitanya Kulkarni
2023-12-07T06:54:02Z

On 12/6/23 20:31, 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".
>
> Signed-off-by: Li Feng <fengli@smartx.com>
> ---
>

This patch looks good to me, however I'd update the commit log and add
performance numbers for the non-mq case also, just in-case to show that we
are not breaking non-mq setup.

Being said that, in case we want to be future proof, we can also think of
adding a module param so if someone comes with a scenario where NO_SCHED is
not providing the performance then they can just use the module parameter
instead of again editing the code, irrespective of that :-

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

-ck