Re: [PATCH] cfq-iosched: fix the delay of cfq_group's vdisktime under iops mode

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Vivek,

On 2017/3/4 3:53, Vivek Goyal wrote:
> On Fri, Mar 03, 2017 at 09:20:44PM +0800, Hou Tao wrote:
> 
> [..]
>>> Frankly, vdisktime is in fixed-point precision shifted by
>>> CFQ_SERVICE_SHIFT so using CFQ_IDLE_DELAY does not make much sense in any
>>> case and just adding 1 to maximum vdisktime should be fine in all the
>>> cases. But that would require more testing whether I did not miss anything
>>> subtle.
> 
> I think even 1 will work. But in the beginning IIRC I took the idea
> from cpu scheduler. Adding a value bigger than 1 will allow you to add
> some other group later before this group. (If you want to give that group
> higher priority).
I still don't understand why using a value bigger than 1 will allow a later added
group to have a vdisktime less than the firstly added group. Could you explain it
in more detail ?

Regards,

Tao

> Thanks
> Vivek
> 
> .
> 




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]