Re: Block IO Controller V4

[Gui Jianfeng <guijianfeng@cn.fujitsu.com>]

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