Messages in this thread Patch in this message | | | From | Qais Yousef <> | Subject | [PATCH v2 6/9] sched/uclamp: Make cpu_overutilized() use util_fits_cpu() | Date | Thu, 4 Aug 2022 15:36:06 +0100 |
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So that it is now uclamp aware.
This fixes a major problem of busy tasks capped with UCLAMP_MAX keeping the system in overutilized state which disables EAS and leads to wasting energy in the long run.
Without this patch running a busy background activity like JIT compilation on Pixel 6 causes the system to be in overutilized state 74.5% of the time.
With this patch this goes down to 9.79%.
It also fixes another problem when long running tasks that have their UCLAMP_MIN changed while running such that they need to upmigrate to honour the new UCLAMP_MIN value. The upmigration doesn't get triggered because overutilized state never gets set in this state, hence misfit migration never happens at tick in this case until the task wakes up again.
Fixes: af24bde8df202 ("sched/uclamp: Add uclamp support to energy_compute()") Signed-off-by: Qais Yousef <qais.yousef@arm.com> --- kernel/sched/fair.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 38cf56ade66d..4c3a5240d7e3 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5807,7 +5807,10 @@ static inline void hrtick_update(struct rq *rq) #ifdef CONFIG_SMP static inline bool cpu_overutilized(int cpu) { - return !fits_capacity(cpu_util_cfs(cpu), capacity_of(cpu)); + unsigned long rq_util_min = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MIN); + unsigned long rq_util_max = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MAX); + + return !util_fits_cpu(cpu_util_cfs(cpu), rq_util_min, rq_util_max, cpu); } static inline void update_overutilized_status(struct rq *rq) -- 2.25.1
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