cpuidle: menu: Lookup CPU runqueues less

The menu governer makes separate lookups of the CPU runqueue to get
load and number of IO waiters but it can be done with a single lookup.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Mel Gorman
2014-08-06 14:19:21 +01:00
committed by Rafael J. Wysocki
parent 64b4ca5cb6
commit 372ba8cb46
4 changed files with 15 additions and 19 deletions
+7 -10
View File
@@ -134,12 +134,9 @@ struct menu_device {
#define LOAD_INT(x) ((x) >> FSHIFT)
#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
static int get_loadavg(void)
static inline int get_loadavg(unsigned long load)
{
unsigned long this = this_cpu_load();
return LOAD_INT(this) * 10 + LOAD_FRAC(this) / 10;
return LOAD_INT(load) * 10 + LOAD_FRAC(load) / 10;
}
static inline int which_bucket(unsigned int duration, unsigned long nr_iowaiters)
@@ -175,13 +172,13 @@ static inline int which_bucket(unsigned int duration, unsigned long nr_iowaiters
* to be, the higher this multiplier, and thus the higher
* the barrier to go to an expensive C state.
*/
static inline int performance_multiplier(unsigned long nr_iowaiters)
static inline int performance_multiplier(unsigned long nr_iowaiters, unsigned long load)
{
int mult = 1;
/* for higher loadavg, we are more reluctant */
mult += 2 * get_loadavg();
mult += 2 * get_loadavg(load);
/* for IO wait tasks (per cpu!) we add 5x each */
mult += 10 * nr_iowaiters;
@@ -296,7 +293,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
int i;
unsigned int interactivity_req;
unsigned long nr_iowaiters;
unsigned long nr_iowaiters, cpu_load;
if (data->needs_update) {
menu_update(drv, dev);
@@ -312,7 +309,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
/* determine the expected residency time, round up */
data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length());
nr_iowaiters = nr_iowait_cpu(smp_processor_id());
get_iowait_load(&nr_iowaiters, &cpu_load);
data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);
/*
@@ -331,7 +328,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* duration / latency ratio. Adjust the latency limit if
* necessary.
*/
interactivity_req = data->predicted_us / performance_multiplier(nr_iowaiters);
interactivity_req = data->predicted_us / performance_multiplier(nr_iowaiters, cpu_load);
if (latency_req > interactivity_req)
latency_req = interactivity_req;