Messages in this thread | | | Date | Tue, 6 Sep 2011 02:35:50 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 06/32] nohz: Move idle ticks stats tracking out of nohz handlers |
| |
On Mon, Aug 29, 2011 at 04:28:08PM +0200, Peter Zijlstra wrote: > On Mon, 2011-08-15 at 17:52 +0200, Frederic Weisbecker wrote: > > Idle ticks time tracking is merged into nohz stop/restart > > handlers. Pull it out into idle entry/exit handlers instead, > > so that nohz APIs is more idle independant. > > Are you trying to say: > > Currently idle time tracking is part of the nohz state tracking, > separate this so that we can disable the tick while we're non-idle?
Right.
> > If so, how does idle time tracking work on a !NOHZ kernel, surely such > things can be idle too..
In that case the tick calls account_process_tick() which delegates to account_idle_time() if we are idle on tick.
That's also used in NOHZ kernels in fact.
In every tick we call account_process_tick(), but when the tick is stopped we save its value in ts->idle_jiffies and when it is restarted we account jiffies - ts->idle_jiffies.
| |