[PATCH 2/6] cpuidle: menu: Compute first_idx when latency_req is known

Rafael J. Wysocki
2018-10-02T21:42:56Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Since menu_select() can only set first_idx to 1 if the exit latency
of the second state is not greater than the latency limit, it should
first determine that limit. Thus first_idx should be computed after
the "interactivity" factor has been taken into account.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpuidle/governors/menu.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)

Index: linux-pm/drivers/cpuidle/governors/menu.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/governors/menu.c
+++ linux-pm/drivers/cpuidle/governors/menu.c
@@ -322,22 +322,6 @@ static int menu_select(struct cpuidle_dr
expected_interval = get_typical_interval(data);
expected_interval = min(expected_interval, data->next_timer_us);

- first_idx = 0;
- if (drv->states[0].flags & CPUIDLE_FLAG_POLLING) {
- struct cpuidle_state *s = &drv->states[1];
- unsigned int polling_threshold;
-
- /*
- * Default to a physical idle state, not to busy polling, unless
- * a timer is going to trigger really really soon.
- */
- polling_threshold = max_t(unsigned int, 20, s->target_residency);
- if (data->next_timer_us > polling_threshold &&
- latency_req > s->exit_latency && !s->disabled &&
- !dev->states_usage[1].disable)
- first_idx = 1;
- }
-
/*
* Use the lowest expected idle interval to pick the idle state.
*/
@@ -364,6 +348,22 @@ static int menu_select(struct cpuidle_dr
latency_req = interactivity_req;
}

+ first_idx = 0;
+ if (drv->states[0].flags & CPUIDLE_FLAG_POLLING) {
+ struct cpuidle_state *s = &drv->states[1];
+ unsigned int polling_threshold;
+
+ /*
+ * Default to a physical idle state, not to busy polling, unless
+ * a timer is going to trigger really really soon.
+ */
+ polling_threshold = max_t(unsigned int, 20, s->target_residency);
+ if (data->next_timer_us > polling_threshold &&
+ latency_req > s->exit_latency && !s->disabled &&
+ !dev->states_usage[1].disable)
+ first_idx = 1;
+ }
+
/*
* Find the idle state with the lowest power while satisfying
* our constraints.