Venki Pallipadi <[EMAIL PROTECTED]> writes:
>
> +void tick_nohz_stop_idle(int cpu)
> +{
> + struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
> +
> + if (ts->idle_active) {
> + ktime_t now, delta;
> + now = ktime_get();
That could be PM timer read costing thousands of cycles.
For going into idle it's probably not a real problem, but it could
seriously affect out of idle latencies.
You would really need a cheaper per CPU timer that doesn't
stop in idle (which rules out sched_clock). It's all unfortunately
quite messy.
-Andi
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