On 01/02/2020 05:10, Jens Axboe wrote:
> 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 :-)
> 
Yep, I didn't abandon it.

-- 
Pavel Begunkov