linux-kernel - Re: [PATCH v2 0/2] Optimise io

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Message-ID: <df612e90-8999-0085-d2d6-4418e044e429@gmail.com>
Date:   Mon, 23 Sep 2019 19:32:34 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Ingo Molnar <mingo@...nel.org>, Jens Axboe <axboe@...nel.dk>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/2] Optimise io_uring completion waiting

Sorry, mixed the threads.

>>
>> I'm not sure an extension is needed for such a special interface, why not 
>> just put a ->threshold value next to the ctx->wait field and use either 
>> the regular wait_event() APIs with the proper condition, or 
>> wait_event_cmd() style APIs if you absolutely need something more complex 
>> to happen inside?
Ingo,
io_uring works well without this patch just using wait_event_*() with
proper condition, but there are performance issues with spurious
wakeups. Detailed description in the previous mail.
Am I missing something?
Thanks


>>
>> Should result in a much lower linecount and no scheduler changes. :-)
>>
>> Thanks,
>>
>> 	Ingo
>>
> 

-- 
Yours sincerely,
Pavel Begunkov



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