Re: [ANNOUNCEMENT] io_uring SQPOLL sharing changes

[Jens Axboe <axboe@kernel.dk>]

On 3/22/21 10:09 PM, Joseph Qi wrote:
> 
> 
> On 3/22/21 10:49 PM, Jens Axboe wrote:
>> On 3/21/21 11:54 PM, Xiaoguang Wang wrote:
>>> hi Pavel,
>>>
>>>> Hey,
>>>>
>>>> You may have already noticed, but there will be a change how SQPOLL
>>>> is shared in 5.12. In particular, SQPOLL may be shared only by processes
>>>> belonging to the same thread group. If this condition is not fulfilled,
>>>> then it silently creates a new SQPOLL task.
>>>
>>> Thanks for your kindly reminder, currently we only share sqpoll thread
>>> in threads belonging to one same process.
>>
>> That's good to know, imho it is also the only thing that _really_ makes
>> sense to do.
>>
>> Since we're on the topic, are you actively using the percpu thread setup
>> that you sent out patches for earlier? That could still work within
>> the new scheme of having io threads, but I'd be curious to know first
>> if you guys are actually using it.
>>
> 
> Yes, we've already used percpu sqthread feature in our production
> environment, in which 16 application threads share the same sqthread,
> and it gains ~20% rt improvement compared with libaio.

Great! Any chance I can get you to re-post the patches against the
current tree?

-- 
Jens Axboe