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Merge remote-tracking branch 'lsk/v3.10/topic/big.LITTLE' into linux-linaro-lsk

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This commit is contained in:
Mark Brown
2014-05-07 14:55:58 +01:00
parent 03b1200275 970a8e6b53
commit 2cae6ea4bb
1 changed files with 24 additions and 10 deletions
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34
kernel/sched/fair.c
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@@ -3703,15 +3703,29 @@ unsigned int hmp_next_up_threshold = 4096;
unsigned int hmp_next_down_threshold = 4096;
#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
#ifndef CONFIG_ARCH_VEXPRESS_TC2
/*
* Set the default packing threshold to try to keep little
* CPUs at no more than 80% of their maximum frequency if only
* packing a small number of small tasks. Bigger tasks will
* raise frequency as normal.
* In order to pack a task onto a CPU, the sum of the
* unweighted runnable_avg load of existing tasks plus the
* load of the new task must be less than hmp_full_threshold.
*
* This works in conjunction with frequency-invariant load
* and DVFS governors. Since most DVFS governors aim for 80%
* utilisation, we arrive at (0.8*0.8*(max_load=1024))=655
* and use a value slightly lower to give a little headroom
* in the decision.
* Note that the most efficient frequency is different for
* each system so /sys/kernel/hmp/packing_limit should be
* configured at runtime for any given platform to achieve
* optimal energy usage. Some systems may not benefit from
* packing, so this feature can also be disabled at runtime
* with /sys/kernel/hmp/packing_enable
*/
unsigned int hmp_packing_enabled = 1;
unsigned int hmp_full_threshold = (NICE_0_LOAD * 9) / 8;
#else
/* TC2 has a sharp consumption curve @ around 800Mhz, so
we aim to spread the load around that frequency. */
unsigned int hmp_packing_enabled;
unsigned int hmp_full_threshold = 650; /* 80% of the 800Mhz freq * NICE_0_LOAD */
#endif
unsigned int hmp_full_threshold = 650;
#endif
static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_entity *se);
@@ -3807,8 +3821,8 @@ static inline unsigned int hmp_select_slower_cpu(struct task_struct *tsk,
* Select the 'best' candidate little CPU to wake up on.
* Implements a packing strategy which examines CPU in
* logical CPU order, and selects the first which will
* have at least 10% capacity available, according to
* both tracked load of the runqueue and the task.
* be loaded less than hmp_full_threshold according to
* the sum of the tracked load of the runqueue and the task.
*/
static inline unsigned int hmp_best_little_cpu(struct task_struct *tsk,
int cpu) {