linux-kernel - Re: [PATCH 0/3]CFQ: add think time check for service tree and group

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Message-ID: <4E1ADE39.6090609@fusionio.com>
Date:	Mon, 11 Jul 2011 13:27:53 +0200
From:	Jens Axboe <jaxboe@...ionio.com>
To:	Shaohua Li <shaohua.li@...el.com>
CC:	lkml <linux-kernel@...r.kernel.org>,
	Vivek Goyal <vgoyal@...hat.com>
Subject: Re: [PATCH 0/3]CFQ: add think time check for service tree and group

On 2011-07-11 07:44, Shaohua Li wrote:
> 2011/7/4 Shaohua Li <shaohua.li@...el.com>:
>> Hi,
>>  Currently when the last queue of a service tree/group is empty, CFQ
>> doesn't expire the queue. This is to allow requests from the tree/group
>> come soon, so tree/group doesn't miss its share. But if the think time
>> is big, the assumption isn't correct. idling the queue is just wasting
>> bandwidth.
>>
>> Originally I was hoping this can resolve Vivek's fsync issue, but it
>> doesn't. The fsync issue is caused by queue idling. But since think time
>> check only helps for think time above default queue idle time (8ms),
>> think time check doesn't help.
>>
>> On the other hand, think time check is still helpful for queues with
>> think time. I had test case in follow patches show throughput
>> improvement without sacrifice tree/group shares.
>>
> Jens,
> can you look at the patches? I refreshed some patches in replying
> Vivek, I can resend if required.

Please resend the series after a refresh like that, otherwise I tend to
lose track of the various things flying around.

-- 
Jens Axboe

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