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From: Jens Axboe <[email protected]>
To: Pavel Begunkov <[email protected]>,
	[email protected], [email protected]
Subject: Re: [PATCH v3 0/6] add persistent submission state
Date: Fri, 31 Jan 2020 19:10:41 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 1/31/20 5:31 PM, Pavel Begunkov wrote:
> On 01/02/2020 01:32, Pavel Begunkov wrote:
>> On 01/02/2020 01:22, Jens Axboe wrote:
>>> On 1/31/20 3:15 PM, Pavel Begunkov wrote:
>>>> Apart from unrelated first patch, this persues two goals:
>>>>
>>>> 1. start preparing io_uring to move resources handling into
>>>> opcode specific functions
>>>>
>>>> 2. make the first step towards long-standing optimisation ideas
>>>>
>>>> Basically, it makes struct io_submit_state embedded into ctx, so
>>>> easily accessible and persistent, and then plays a bit around that.
>>>
>>> Do you have any perf/latency numbers for this? Just curious if we
>>> see any improvements on that front, cross submit persistence of
>>> alloc caches should be a nice sync win, for example, or even
>>> for peak iops by not having to replenish the pool for each batch.
>>>
>>> I can try and run some here too.
>>>
>>
>> I tested the first version, but my drive is too slow, so it was only nops and
>> hence no offloading. Honestly, there waren't statistically significant results.
>> I'll rerun anyway.
>>
>> I have a plan to reuse it for a tricky optimisation, but thinking twice, I can
>> just stash it until everything is done. That's not the first thing in TODO and
>> will take a while.
>>
> 
> I've got numbers, but there is nothing really interesting. Throughput is
> insignificantly better with the patches, but I'd need much more experiments
> across reboots to confirm that.
> 
> Let's postpone the patchset for later

Sounds fine to me, no need to do it unless it's a nice cleanup, and/or
provides some nice improvements.

It would be great to see the splice stuff revamped, though :-)

-- 
Jens Axboe


  reply	other threads:[~2020-02-01  2:10 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-31 22:15 [PATCH v3 0/6] add persistent submission state Pavel Begunkov
2020-01-31 22:15 ` [PATCH v3 1/6] io_uring: always pass non-null io_submit_state Pavel Begunkov
2020-01-31 22:15 ` [PATCH v3 2/6] io_uring: place io_submit_state into ctx Pavel Begunkov
2020-01-31 22:15 ` [PATCH v3 3/6] io_uring: move ring_fd into io_submit_state Pavel Begunkov
2020-01-31 22:15 ` [PATCH v3 4/6] io_uring: move *link " Pavel Begunkov
2020-01-31 22:15 ` [PATCH v3 5/6] io_uring: persistent req bulk allocation cache Pavel Begunkov
2020-01-31 22:15 ` [PATCH v3 6/6] io_uring: optimise " Pavel Begunkov
2020-01-31 22:22 ` [PATCH v3 0/6] add persistent submission state Jens Axboe
2020-01-31 22:32   ` Pavel Begunkov
2020-02-01  0:31     ` Pavel Begunkov
2020-02-01  2:10       ` Jens Axboe [this message]
2020-02-01 11:42         ` Pavel Begunkov

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