From: Rafael J. Wysocki <[email protected]> If the next timer event (with the tick excluded) is closer than the target residency of the second state or the PM QoS latency constraint is below its exit latency, state[0] will be used regardless of any other factors, so skip the computations in menu_select() then and return 0 straight away from it.
Still, do that after the bucket has been determined to avoid disturbing the wakeup statistics in general. Signed-off-by: Rafael J. Wysocki <[email protected]> --- drivers/cpuidle/governors/menu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) Index: linux-pm/drivers/cpuidle/governors/menu.c =================================================================== --- linux-pm.orig/drivers/cpuidle/governors/menu.c +++ linux-pm/drivers/cpuidle/governors/menu.c @@ -309,6 +309,18 @@ static int menu_select(struct cpuidle_dr get_iowait_load(&nr_iowaiters, &cpu_load); data->bucket = which_bucket(data->next_timer_us, nr_iowaiters); + if (unlikely(drv->state_count <= 1) || + ((data->next_timer_us < drv->states[1].target_residency || + latency_req < drv->states[1].exit_latency) && + !drv->states[0].disabled && !dev->states_usage[0].disable)) { + /* + * In this case state[0] will be used no matter what, so return + * it right away and keep the tick running. + */ + *stop_tick = false; + return 0; + } + /* * Force the result of multiplication to be 64 bits even if both * operands are 32 bits.
