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From: Gui Jianfeng <>
To: Vivek Goyal <>
Cc: Chad Talbott <>, Jens Axboe <>,
	Shaohua Li <>,
	lkml <>,
	Divyesh Shah <>
Subject: Re: [PATCH 0/6 v4] cfq-iosched: Introduce CFQ group hierarchical scheduling and "use_hierarchy" interface
Date: Tue, 15 Feb 2011 11:13:48 +0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Vivek Goyal wrote:
> On Sat, Feb 12, 2011 at 02:08:54PM +0800, Gui Jianfeng wrote:
>> Vivek Goyal wrote:
>>> On Thu, Feb 10, 2011 at 03:45:45PM +0800, Gui Jianfeng wrote:
>>>> Hi
>>>> Previously, I posted a patchset to add support of CFQ group hierarchical scheduling
>>>> in the way that it puts all CFQ queues in a hidden group and schedules with other 
>>>> CFQ group under their parent. The patchset is available here,
>>>> Vivek think this approach isn't so instinct that we should treat CFQ queues
>>>> and groups at the same level. Here is the new approach for hierarchical 
>>>> scheduling based on Vivek's suggestion. The most big change of CFQ is that
>>>> it gets rid of cfq_slice_offset logic, and makes use of vdisktime for CFQ
>>>> queue scheduling just like CFQ group does. But I still give cfqq some jump 
>>>> in vdisktime based on ioprio, thanks for Vivek to point out this. Now CFQ 
>>>> queue and CFQ group use the same scheduling algorithm. 
>>>> "use_hierarchy" interface is now added to switch between hierarchical mode
>>>> and flat mode. It works as memcg.
>>>> --
>>>> V3 -> V4 Changes:
>>>> - Take io class into account when calculating the boost value.
>>>> - Refine the vtime boosting logic as Vivek's Suggestion.
>>> Hi Gui,
>>> What testing did you do to make sure that this vtime boosting logic is working
>>> and is good replacement for slice_offset() logic for cfqq?
>>> Secondly, did you get a chance to look at chad's patch of keeping track
>>> of previous assigned vdisktime and keeping track of genrations. I think
>>> his patch is going to coflict with yours, so one of you will have to
>>> make adjustments. I think both the boost logic and keeping track of generation
>>> logic can be combined.
>> Hi Vivek,
>> For the time being, boosting logic only works for cfq queue, and keepinging track of
>> generation works for cfq group.
>> I think when we introduce boosting logic for cfq group, we can combine these two logic
>> together.
> Ok, I am assuming that now you are introducing another patch in the series
> to get boosting logic working for groups also.
> Also, it might be easier to test it with group_idle=0, as right now groups
> don't preempt each other.


If you don't object, I'd like to introduce this in a seperate patch when this series
gets merged. For I don't want to add more complexity for this seires. ;) 
I'll post v5.


> Thanks
> Vivek

  reply	other threads:[~2011-02-15  3:13 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-10  7:45 Gui Jianfeng
2011-02-10 18:30 ` Vivek Goyal
2011-02-11  9:58   ` Gui Jianfeng
2011-02-12  6:08   ` Gui Jianfeng
2011-02-14 18:06     ` Vivek Goyal
2011-02-15  3:13       ` Gui Jianfeng [this message]
2011-02-15 14:29         ` Vivek Goyal

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