Re: [PATCHSET/RFC v2] blk-mq scheduling framework

From: Paolo Valente
Date: Tue Dec 13 2016 - 11:16:44 EST



> Il giorno 13 dic 2016, alle ore 16:17, Jens Axboe <axboe@xxxxxx> ha scritto:
>
> On Tue, Dec 13 2016, Paolo Valente wrote:
>>
>>> Il giorno 08 dic 2016, alle ore 21:13, Jens Axboe <axboe@xxxxxx> ha scritto:
>>>
>>> As a followup to this posting from yesterday:
>>>
>>> https://marc.info/?l=linux-block&m=148115232806065&w=2
>>>
>>> this is version 2. I wanted to post a new one fairly quickly, as there
>>> ended up being a number of potential crashes in v1. This one should be
>>> solid, I've run mq-deadline on both NVMe and regular rotating storage,
>>> and we handle the various merging cases correctly.
>>>
>>> You can download it from git as well:
>>>
>>> git://git.kernel.dk/linux-block blk-mq-sched.2
>>>
>>> Note that this is based on for-4.10/block, which is in turn based on
>>> v4.9-rc1. I suggest pulling it into my for-next branch, which would
>>> then merge nicely with 'master' as well.
>>>
>>
>> Hi Jens,
>> this is just to tell you that I have finished running some extensive
>> tests on this patch series (throughput, responsiveness, low latency
>> for soft real time). No regression w.r.t. blk detected, and no
>> crashes or other anomalies.
>>
>> Starting to work on BFQ port. Please be patient with my little
>> expertise on mq environment, and with my next silly questions!
>
> No worries, ask away if you have questions. As you might have seen, it's
> still a little bit of a moving target, but it's getting closer every
> day. I'll post a v3 later today hopefully that will be a good fix point
> for you. I'll need to add the io context setup etc, that's not there
> yet, as only cfq/bfq uses that.
>

You anticipated the question that was worrying me more, how to handle
iocontexts :) I'll go on studying your patches while waiting for this
(last, right?) missing piece for bfq.

Should you implement a modified version of cfq, to test your last
extensions, I would of course appreciate very much to have a look at
it (if you are willing to share it, of course).

Thanks,
Paolo


> --
> Jens Axboe