On Tue, Jul 08, 2014 at 10:51:02AM +0800, xiaofeng.yan wrote:
On 2014/7/8 10:40, Li Zefan wrote:Ah, thanks. Be advised that currently HRTICK is rather expensive. The
On 2014/7/8 9:10, xiaofeng.yan wrote:Thanks for your timely comments. In fact, We use HRTICK feature in product.
On 2014/7/7 16:41, Peter Zijlstra wrote:I think what peter meant is, do you use HRTICK in products or
On Fri, Jul 04, 2014 at 12:02:21PM +0000, xiaofeng.yan wrote:yes, If HRTICK is close , then all of runtime and deadline will be wrong.
It could be wrong for the precision of runtime and deadlineAre you actually using HRTICK ?
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
just use it for testing/experiment?
We need microsecond level
cost is twofold: 1) doing all the kernel side hrtimer things and 2)
programming clock hardware.
Of course, if that's what you need, you're willing to pay the price.
I'll see if I can put making it less expensive slightly higher on the
(endless) todo list.