lkml.org 
[lkml]   [2010]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Sched_class documentation
From
Date
On Thu, 2010-06-17 at 19:02 +0200, sebastiano spicuglia wrote:
> Hi Ingo,
>
> I made many progress. But I have two doubts yet.
> First: what does hrtick_start do?

higher resolution ticks

> I think that: if I call hrtick_start(rq, 500) then, after 500ns, the
> task_tick function will be invocated.
> Is it right?

Yep, instead of waiting for the next system tick is programs a hrtimer
to deliver it -- its disabled by default though, since programming
timers is rather expensive :/

> Second: if my schedule_class decides to preempt the current task, it
> has to call resched_task(rq->curr).
> Is it right?

Either that or resched_cpu(), depending on which is most convenient.

It sets TIF_RESCHED and possibly IPIs the remote CPU. The TIF flag is
then observed (on re-entry to userspace in case of the IPI) and we call
into schedule().


\
 
 \ /
  Last update: 2010-06-17 19:15    [W:0.069 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site