Re: [PATCH] block/mq-deadline: Speed up the dispatch of low-priority requests

["Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>]

On 2021/8/27 11:13, Jens Axboe wrote:
> On 8/26/21 8:48 PM, Bart Van Assche wrote:
>> On 8/26/21 5:05 PM, Jens Axboe wrote:
>>> On 8/26/21 6:03 PM, Bart Van Assche wrote:
>>>> Here is an overview of the tests I ran so far, all on the same test
>>>> setup:
>>>> * No I/O scheduler:               about 5630 K IOPS.
>>>> * Kernel v5.11 + mq-deadline:     about 1100 K IOPS.
>>>> * block-for-next + mq-deadline:   about  760 K IOPS.
>>>> * block-for-next with improved mq-deadline performance: about 970 K IOPS.
>>>
>>> So we're still off by about 12%, I don't think that is good enough.
>>> That's assuming that v5.11 + mq-deadline is the same as for-next with
>>> the mq-deadline change reverted? Because that would be the key number to
>>> compare it with.
>>
>> With the patch series that is available at
>> https://github.com/bvanassche/linux/tree/block-for-next the same test reports
>> 1090 K IOPS or only 1% below the v5.11 result. I will post that series on the
>> linux-block mailing list after I have finished testing that series.
> 
> OK sounds good. I do think we should just do the revert at this point,
> any real fix is going to end up being bigger than I'd like at this
> point. Then we can re-introduce the feature once we're happy with the
> results.

Yes, It's already rc7 and it's no longer good for big changes. Revert is the
best solution, and apply my patch is a compromise solution.

>