Re: [PATCH] sched/rt: overrun could happen in start_hrtick_dl

[xiaofeng.yan]

On 2014/7/8 10:40, Li Zefan wrote:
> On 2014/7/8 9:10, xiaofeng.yan wrote:
> > On 2014/7/7 16:41, Peter Zijlstra wrote:
> > > On Fri, Jul 04, 2014 at 12:02:21PM +0000, xiaofeng.yan wrote:
> > > > It could be wrong for the precision of runtime and deadline
> > > > when the precision is within microsecond level. For example:
> > > > Task runtime deadline period
> > > >    P1   200us   500us   500us
> > > >
> > > > This case need enbale HRTICK feature by the next command
> > > > PC#echo "HRTICK" > /sys/kernel/debug/sched_features
> > > > PC#./schedtool -E -t 200000:500000 -e ./test&
> > > > PC#trace-cmd record -e sched_switch
> > > Are you actually using HRTICK ?
> > yes, If HRTICK is close , then all of runtime and deadline will be wrong.
> I think what peter meant is, do you use HRTICK in products or
> just use it for testing/experiment?
Thanks for your timely comments. In fact, We use HRTICK feature in 
product. We need microsecond level
precision.

Thanks
Yan
> .


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