Re: [RFC][PATCH 9/9] cpuidle: Use local_clock_noinstr()

Rafael J. Wysocki
2023-05-09T16:18:23Z

On Mon, May 8, 2023 at 11:34 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> With the introduction of local_clock_noinstr(), local_clock() itself
> is no longer marked noinstr, use the correct function.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> drivers/cpuidle/cpuidle.c | 8 ++++----
> drivers/cpuidle/poll_state.c | 4 ++--
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -145,7 +145,7 @@ static noinstr void enter_s2idle_proper(
>
> instrumentation_begin();
>
> - time_start = ns_to_ktime(local_clock());
> + time_start = ns_to_ktime(local_clock_noinstr());
>
> tick_freeze();
> /*
> @@ -169,7 +169,7 @@ static noinstr void enter_s2idle_proper(
> tick_unfreeze();
> start_critical_timings();
>
> - time_end = ns_to_ktime(local_clock());
> + time_end = ns_to_ktime(local_clock_noinstr());
>
> dev->states_usage[index].s2idle_time += ktime_us_delta(time_end, time_start);
> dev->states_usage[index].s2idle_usage++;
> @@ -243,7 +243,7 @@ noinstr int cpuidle_enter_state(struct c
> sched_idle_set_state(target_state);
>
> trace_cpu_idle(index, dev->cpu);
> - time_start = ns_to_ktime(local_clock());
> + time_start = ns_to_ktime(local_clock_noinstr());
>
> stop_critical_timings();
> if (!(target_state->flags & CPUIDLE_FLAG_RCU_IDLE)) {
> @@ -276,7 +276,7 @@ noinstr int cpuidle_enter_state(struct c
> start_critical_timings();
>
> sched_clock_idle_wakeup_event();
> - time_end = ns_to_ktime(local_clock());
> + time_end = ns_to_ktime(local_clock_noinstr());
> trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu);
>
> /* The cpu is no longer idle or about to enter idle. */
> --- a/drivers/cpuidle/poll_state.c
> +++ b/drivers/cpuidle/poll_state.c
> @@ -15,7 +15,7 @@ static int __cpuidle poll_idle(struct cp
> {
> u64 time_start;
>
> - time_start = local_clock();
> + time_start = local_clock_noinstr();
>
> dev->poll_time_limit = false;
>
> @@ -32,7 +32,7 @@ static int __cpuidle poll_idle(struct cp
> continue;
>
> loop_count = 0;
> - if (local_clock() - time_start > limit) {
> + if (local_clock_noinstr() - time_start > limit) {
> dev->poll_time_limit = true;
> break;
> }
>

The above LGTM, but the teo governors uses local_clock() too. Should
it use the _noinstr() version?