Messages in this thread Patch in this message | | | Date | Thu, 30 May 2013 09:48:58 +0800 | From | Alex Shi <> | Subject | Re: [PATCH 1/2] sched: Use do_div() for 64 bit division at power utilization calculation (putil) |
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On 05/23/2013 04:34 PM, Lukasz Majewski wrote: > Now explicit casting is done when power usage variable (putil) is calculated > > Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> > --- > This patch was developed on top of the following Alex's repository: > https://github.com/alexshi/power-scheduling/commits/power-scheduling > --- > kernel/sched/fair.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) >
Thanks for catch this issue. seems use div_u64 is better, and there are 2 same bugs. so, could I rewrite the patch like following? ---
From 9f72c25607351981898d99822f5a66e0ca67a3da Mon Sep 17 00:00:00 2001 From: Alex Shi <alex.shi@intel.com> Date: Wed, 29 May 2013 11:09:39 +0800 Subject: [PATCH 1/2] sched: fix cast on power utilization calculation and use div_u64
Now explicit casting is done when power usage variable (putil) is calculated. div_u64 is optimized on u32.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Alex Shi <alex.shi@intel.com> --- kernel/sched/fair.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 09ae48a..3a4917c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1504,8 +1504,8 @@ static inline void update_rq_runnable_avg(struct rq *rq, int runnable) __update_tg_runnable_avg(&rq->avg, &rq->cfs); period = rq->avg.runnable_avg_period ? rq->avg.runnable_avg_period : 1; - rq->util = (u64)(rq->avg.runnable_avg_sum << SCHED_POWER_SHIFT) - / period; + rq->util = div_u64(((u64)rq->avg.runnable_avg_sum << SCHED_POWER_SHIFT), + period); } /* Add the load generated by se into cfs_rq's child load-average */ @@ -3407,8 +3407,8 @@ static int is_sd_full(struct sched_domain *sd, /* p maybe a new forked task */ putil = FULL_UTIL; else - putil = (u64)(p->se.avg.runnable_avg_sum << SCHED_POWER_SHIFT) - / (p->se.avg.runnable_avg_period + 1); + putil = div_u64(((u64)p->se.avg.runnable_avg_sum << SCHED_POWER_SHIFT), + p->se.avg.runnable_avg_period + 1); /* Try to collect the domain's utilization */ group = sd->groups; @@ -3463,9 +3463,11 @@ find_leader_cpu(struct sched_group *group, struct task_struct *p, int this_cpu, int vacancy, min_vacancy = INT_MAX; int leader_cpu = -1; int i; + /* percentage of the task's util */ - unsigned putil = (u64)(p->se.avg.runnable_avg_sum << SCHED_POWER_SHIFT) - / (p->se.avg.runnable_avg_period + 1); + unsigned putil; + putil = div_u64(((u64)p->se.avg.runnable_avg_sum << SCHED_POWER_SHIFT), + p->se.avg.runnable_avg_period + 1); /* bias toward local cpu */ if (cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p)) && -- 1.7.12
-- Thanks Alex
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