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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2018-10-03 00:46:28 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2018-10-04 20:27:27 +0300 |
| commit | 8b007ebec9a5d120d25c00d9b771aadf45ac5177 (patch) | |
| tree | 1b6cf4c40c0fbe96f9e2343375e689d9cbc534c3 /drivers/cpuidle | |
| parent | eb40a380bff28f84b6583bba6786b46ef26ef548 (diff) | |
| download | linux-8b007ebec9a5d120d25c00d9b771aadf45ac5177.tar.xz | |
cpuidle: menu: Avoid computations for very close timers
If the next timer event (not including the tick) 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
updating the correction factor for a stale bucket.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/governors/menu.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 968379d4f207..667606c6e284 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -309,6 +309,18 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, 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. |