shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-08 20:07:46 +09:00
Code Issues Packages Projects Releases Wiki Activity

HMP: Explicitly implement all-load-is-max-load policy for HMP targets

Browse Source 
Experimentally, one of the best policies for HMP migration CPU
selection is to completely ignore part-loaded CPUs and only look
for idle ones. If there are no idle ones, we will choose the one
which was least-recently-disturbed.

Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This commit is contained in:
Chris Redpath
2013-07-15 16:06:44 +01:00
committed by Jon Medhurst
parent e580deb7fe
commit 72d74c1196
1 changed files with 20 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
kernel/sched/fair.c
View File

@@ -3959,8 +3959,7 @@ static inline unsigned int hmp_domain_min_load(struct hmp_domain *hmpd,
u64 min_target_last_migration = ULLONG_MAX;
u64 curr_last_migration;
unsigned long min_runnable_load = INT_MAX;
unsigned long scaled_min_runnable_load = INT_MAX;
unsigned long contrib, scaled_contrib;
unsigned long contrib;
struct sched_avg *avg;
for_each_cpu_mask(cpu, hmpd->cpus) {
@@ -3969,12 +3968,17 @@ static inline unsigned int hmp_domain_min_load(struct hmp_domain *hmpd,
curr_last_migration = avg->hmp_last_up_migration ?
avg->hmp_last_up_migration : avg->hmp_last_down_migration;
/* don't use the divisor in the loop, just at the end */
contrib = avg->load_avg_ratio * scale_load_down(1024);
scaled_contrib = contrib >> 13;
contrib = avg->load_avg_ratio;
/*
* Consider a runqueue completely busy if there is any load
* on it. Definitely not the best for overall fairness, but
* does well in typical Android use cases.
*/
if (contrib)
contrib = 1023;
if ((contrib < min_runnable_load) ||
(scaled_contrib == scaled_min_runnable_load &&
(contrib == min_runnable_load &&
curr_last_migration < min_target_last_migration)) {
/*
* if the load is the same target the CPU with
@@ -3984,7 +3988,6 @@ static inline unsigned int hmp_domain_min_load(struct hmp_domain *hmpd,
* domain is fully loaded
*/
min_runnable_load = contrib;
scaled_min_runnable_load = scaled_contrib;
min_cpu_runnable_temp = cpu;
min_target_last_migration = curr_last_migration;
}
@@ -3993,10 +3996,7 @@ static inline unsigned int hmp_domain_min_load(struct hmp_domain *hmpd,
if (min_cpu)
*min_cpu = min_cpu_runnable_temp;
/* domain will often have at least one empty CPU */
trace_printk("hmp_domain_min_load returning %lu\n",
min_runnable_load > 1023 ? 1023 : min_runnable_load);
return min_runnable_load > 1023 ? 1023 : min_runnable_load;
return min_runnable_load;
}
/*
@@ -4023,10 +4023,9 @@ static inline unsigned int hmp_offload_down(int cpu, struct sched_entity *se)
if (hmp_cpu_is_slowest(cpu))
return NR_CPUS;
/* Is the current domain fully loaded? */
/* load < ~50% */
/* Is there an idle CPU in the current domain */
min_usage = hmp_domain_min_load(hmp_cpu_domain(cpu), NULL);
if (min_usage < (NICE_0_LOAD>>1))
if (min_usage == 0)
return NR_CPUS;
/* Is the task alone on the cpu? */
@@ -4038,10 +4037,9 @@ static inline unsigned int hmp_offload_down(int cpu, struct sched_entity *se)
if (hmp_task_starvation(se) > 768)
return NR_CPUS;
/* Does the slower domain have spare cycles? */
/* Does the slower domain have any idle CPUs? */
min_usage = hmp_domain_min_load(hmp_slower_domain(cpu), &dest_cpu);
/* load > 50% */
if (min_usage > NICE_0_LOAD/2)
if (min_usage > 0)
return NR_CPUS;
if (cpumask_test_cpu(dest_cpu, &hmp_slower_domain(cpu)->cpus))
@@ -6501,9 +6499,11 @@ static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_enti
< hmp_next_up_threshold)
return 0;
/* Target domain load < 94% */
if (hmp_domain_min_load(hmp_faster_domain(cpu), target_cpu)
> NICE_0_LOAD-64)
/* hmp_domain_min_load only returns 0 for an
* idle CPU or 1023 for any partly-busy one.
* Be explicit about requirement for an idle CPU.
*/
if (hmp_domain_min_load(hmp_faster_domain(cpu), target_cpu) != 0)
return 0;
if (cpumask_intersects(&hmp_faster_domain(cpu)->cpus,