Message-ID: <4B1CC0BD.1000405@cn.fujitsu.com>
Date: Mon, 07 Dec 2009 16:45:49 +0800
From: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
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To: Vivek Goyal <vgoyal@redhat.com>, jens.axboe@oracle.com
CC: linux-kernel@vger.kernel.org, nauman@google.com, dpshah@google.com,
       lizf@cn.fujitsu.com, ryov@valinux.co.jp, fernando@oss.ntt.co.jp,
       s-uchida@ap.jp.nec.com, taka@valinux.co.jp, jmoyer@redhat.com,
       righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, czoccolo@gmail.com,
       Alan.Brunelle@hp.com
Subject: Re: Block IO Controller V4
References: <1259549968-10369-1-git-send-email-vgoyal@redhat.com> <4B15C828.4080407@cn.fujitsu.com> <20091202142508.GA31715@redhat.com> <4B1779CE.1050801@cn.fujitsu.com> <20091203143641.GA3887@redhat.com> <20091203181003.GD2735@redhat.com> <20091203235153.GG2735@redhat.com>
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Vivek Goyal wrote:
> On Thu, Dec 03, 2009 at 01:10:03PM -0500, Vivek Goyal wrote:
> 
> [..]
>> Hi Gui,
>>
>> Can you please try following patch and see if it helps you. If not, then
>> we need to figure out why we choose to not idle and delete the group from
>> service tree.
>>
> 
> Hi Gui,
> 
> Please try this version of the patch instead of previous one. During more
> testing I saw some additional deletions where we should have waited and
> the reason being that we were hitting boundary condition. At the request
> completion time slice has not expired but after 4-5 ns, select_queue hits
> and jiffy has incremented by then and slice expires.
> 
> ttime_mean, is not covering this condition because this workload is so
> sequential that ttime_mean=0.
> 
> So I am checking for new condition where if we are into last ms of slice,
> mark the queue wait_busy.
> 
> Thanks
> Vivek
> 
> Signed-off-by: Vivek Goyal <vgoyal@redhat.com>

Hi, Vivek

I add some debug message in select_queue, it does meet the boundary condition. 
I tried this patch, and works fine on my box.

Acked-by: Gui Jianfeng <guijiafneng@cn.fujitsu.com>

Thanks,
Gui

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