linux-kernel - Re: [PATCH v5] Subject: io_uring: releasing CPU resources when polling

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Message-ID: <75791526-98d4-4750-8775-9c6ddfea07eb@kernel.dk>
Date: Fri, 28 Jun 2024 15:13:48 -0600
From: Jens Axboe <axboe@...nel.dk>
To: hexue <xue01.he@...sung.com>
Cc: asml.silence@...il.com, io-uring@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5] Subject: io_uring: releasing CPU resources when
 polling

On 6/25/24 2:39 AM, hexue wrote:
> On 6/19/24 15:51, Jens Axboe wrote:
>> On 6/19/24 08:18, hexue wrote:
>>
>> While I do suspect there are cases where hybrid polling will be more
>> efficient, not sure there are many of them. And you're most likely
>> better off just doing IRQ driven IO at that point? Particularly with the
>> fairly substantial overhead of maintaining the data you need, and time
>> querying.
> 
> I rebuilt the test cases based on your information, that is, each drive has
> only one thread with high pressure, there is a significant performance loss.
> I previously provided test data for a single drive with multi-threaded, which
> can achieve performance stable and CPU savings.
> 
> Thanks for your data, I will reduce the cost of each IO and submit the next
> version.

Sounds good, thanks. I don't doubt it's useful for some cases as-is, but
I think there's the potential for it to be more useful.

-- 
Jens Axboe