From: Jens Axboe <jaxboe@fusionio.com>
To: Shaohua Li <shaohua.li@intel.com>
Cc: lkml <linux-kernel@vger.kernel.org>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH 0/3]CFQ: add think time check for service tree and group
Date: Mon, 11 Jul 2011 13:27:53 +0200 [thread overview]
Message-ID: <4E1ADE39.6090609@fusionio.com> (raw)
In-Reply-To: <CANejiEXryM=hawNjQZPYEM2L97+gUYqHQ_YQJ5p5gLTvBkC25Q@mail.gmail.com>
On 2011-07-11 07:44, Shaohua Li wrote:
> 2011/7/4 Shaohua Li <shaohua.li@intel.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
next prev parent reply other threads:[~2011-07-11 11:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-04 5:36 [PATCH 0/3]CFQ: add think time check for service tree and group Shaohua Li
2011-07-11 5:44 ` Shaohua Li
2011-07-11 11:27 ` Jens Axboe [this message]
2011-07-11 13:05 ` Vivek Goyal
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