Messages in this thread | | | Date | Mon, 5 Mar 2018 13:42:17 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC/RFT][PATCH 6/7] sched: idle: Predict idle duration before stopping the tick |
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On Mon, Mar 05, 2018 at 01:07:07PM +0100, Rafael J. Wysocki wrote: > On Mon, Mar 5, 2018 at 12:50 PM, Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Mon, Mar 5, 2018 at 12:45 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> >> So I think this is entirely wrong, I would much rather see something > >> like: > >> > >> tick_nohz_idle_go_idle(next_state->nohz); > >> > >> Where the selected state itself has the nohz property or not. > > > > Can you elaborate here, I'm not following? > > > >> We can always insert an extra state at whatever the right boundary point > >> is for nohz if it doesn't line up with an existing point. > > OK, I guess I know what you mean: to add a state flag meaning "stop > the tick if this state is selected".
Yes, that.
> That could work, but I see problems, like having to go through all of > the already defined states and deciding what to do with them.
Shouldn't be too hard, upon registering a cpuidle driver to the cpuidle core, the core could go through the provided states and flag all those < TICK_USEC as not stopping, all those > TICK_USEC as stopping and splitting the state we'd select for TICK_NSEC sleeps, stopping it for < and disabling it for >.
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