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Date: Fri, 19 Oct 2012 14:18:12 +0200
From: Vincent Guittot <vincent.guittot@...aro.org>
To: pjt@...gle.com
Cc: linux-kernel@...r.kernel.org,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...e.hu>,
Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
Srivatsa Vaddagiri <vatsa@...ibm.com>,
Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>,
Venki Pallipadi <venki@...gle.com>,
Ben Segall <bsegall@...gle.com>,
Mike Galbraith <efault@....de>,
Nikunj A Dadhania <nikunj@...ux.vnet.ibm.com>,
Morten Rasmussen <Morten.Rasmussen@....com>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Namhyung Kim <namhyung@...nel.org>
Subject: Re: [patch 15/16] sched: implement usage tracking
Hi Paul,
I think that you have forgot to reset .usage_avg_sum in the
__sched_fork as it's already done for .runnable_avg_sum and
.usage_avg_sum
And it seems that this reset is not corrected in the latest version in
your git repo:
http://git.kernel.org/?p=linux/kernel/git/pjt/sched.git;a=blob;f=kernel/sched/core.c;h=df55e2ecdd2398648c7d01e318070d06b845a5b0;hb=refs/heads/load_tracking#l1535
Regards,
Vincent
On 23 August 2012 16:14, <pjt@...gle.com> wrote:
> From: Paul Turner <pjt@...gle.com>
>
> With the frame-work for runnable tracking now fully in place. Per-entity usage
> tracking is a simple and low-overhead addition.
>
> Signed-off-by: Paul Turner <pjt@...gle.com>
> Reviewed-by: Ben Segall <bsegall@...gle.com>
> ---
> include/linux/sched.h | 1 +
> kernel/sched/debug.c | 3 +++
> kernel/sched/fair.c | 33 ++++++++++++++++++++++++++++-----
> kernel/sched/sched.h | 4 ++--
> 4 files changed, 34 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 93e27c0..2a4be1f 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1150,6 +1150,7 @@ struct sched_avg {
> u64 last_runnable_update;
> s64 decay_count;
> unsigned long load_avg_contrib;
> + u32 usage_avg_sum;
> };
>
> #ifdef CONFIG_SCHEDSTATS
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 2cd3c1b..b9d54d0 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -94,6 +94,7 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
> #ifdef CONFIG_SMP
> P(se->avg.runnable_avg_sum);
> P(se->avg.runnable_avg_period);
> + P(se->avg.usage_avg_sum);
> P(se->avg.load_avg_contrib);
> P(se->avg.decay_count);
> #endif
> @@ -230,6 +231,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
> cfs_rq->tg_runnable_contrib);
> SEQ_printf(m, " .%-30s: %d\n", "tg->runnable_avg",
> atomic_read(&cfs_rq->tg->runnable_avg));
> + SEQ_printf(m, " .%-30s: %d\n", "tg->usage_avg",
> + atomic_read(&cfs_rq->tg->usage_avg));
> #endif
>
> print_cfs_group_stats(m, cpu, cfs_rq->tg);
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index b249371..44a9a11 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -994,7 +994,8 @@ static u32 __compute_runnable_contrib(u64 n)
> */
> static __always_inline int __update_entity_runnable_avg(u64 now,
> struct sched_avg *sa,
> - int runnable)
> + int runnable,
> + int running)
> {
> u64 delta, periods;
> u32 runnable_contrib;
> @@ -1033,6 +1034,8 @@ static __always_inline int __update_entity_runnable_avg(u64 now,
> delta_w = 1024 - delta_w;
> if (runnable)
> sa->runnable_avg_sum += delta_w;
> + if (running)
> + sa->usage_avg_sum += delta_w;
> sa->runnable_avg_period += delta_w;
>
> delta -= delta_w;
> @@ -1045,17 +1048,22 @@ static __always_inline int __update_entity_runnable_avg(u64 now,
> periods + 1);
> sa->runnable_avg_period = decay_load(sa->runnable_avg_period,
> periods + 1);
> + sa->usage_avg_sum = decay_load(sa->usage_avg_sum, periods + 1);
>
> /* Efficiently calculate \sum (1..n_period) 1024*y^i */
> runnable_contrib = __compute_runnable_contrib(periods);
> if (runnable)
> sa->runnable_avg_sum += runnable_contrib;
> + if (running)
> + sa->usage_avg_sum += runnable_contrib;
> sa->runnable_avg_period += runnable_contrib;
> }
>
> /* Remainder of delta accrued against u_0` */
> if (runnable)
> sa->runnable_avg_sum += delta;
> + if (running)
> + sa->usage_avg_sum += delta;
> sa->runnable_avg_period += delta;
>
> return decayed;
> @@ -1101,16 +1109,28 @@ static inline void __update_tg_runnable_avg(struct sched_avg *sa,
> struct cfs_rq *cfs_rq)
> {
> struct task_group *tg = cfs_rq->tg;
> - long contrib;
> + long contrib, usage_contrib;
>
> /* The fraction of a cpu used by this cfs_rq */
> contrib = div_u64(sa->runnable_avg_sum << NICE_0_SHIFT,
> sa->runnable_avg_period + 1);
> contrib -= cfs_rq->tg_runnable_contrib;
>
> - if (abs(contrib) > cfs_rq->tg_runnable_contrib / 64) {
> + usage_contrib = div_u64(sa->usage_avg_sum << NICE_0_SHIFT,
> + sa->runnable_avg_period + 1);
> + usage_contrib -= cfs_rq->tg_usage_contrib;
> +
> + /*
> + * contrib/usage at this point represent deltas, only update if they
> + * are substantive.
> + */
> + if ((abs(contrib) > cfs_rq->tg_runnable_contrib / 64) ||
> + (abs(usage_contrib) > cfs_rq->tg_usage_contrib / 64)) {
> atomic_add(contrib, &tg->runnable_avg);
> cfs_rq->tg_runnable_contrib += contrib;
> +
> + atomic_add(usage_contrib, &tg->usage_avg);
> + cfs_rq->tg_usage_contrib += usage_contrib;
> }
> }
>
> @@ -1216,7 +1236,8 @@ static inline void update_entity_load_avg(struct sched_entity *se,
> else
> now = cfs_rq_clock_task(group_cfs_rq(se));
>
> - if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq))
> + if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq,
> + cfs_rq->curr == se))
> return;
>
> contrib_delta = __update_entity_load_avg_contrib(se);
> @@ -1261,7 +1282,8 @@ static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update)
>
> static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
> {
> - __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable);
> + __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable,
> + runnable);
> __update_tg_runnable_avg(&rq->avg, &rq->cfs);
> }
>
> @@ -1629,6 +1651,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
> */
> update_stats_wait_end(cfs_rq, se);
> __dequeue_entity(cfs_rq, se);
> + update_entity_load_avg(se, 1);
> }
>
> update_stats_curr_start(cfs_rq, se);
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 89a0e38..e14601e 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -113,7 +113,7 @@ struct task_group {
>
> atomic_t load_weight;
> atomic64_t load_avg;
> - atomic_t runnable_avg;
> + atomic_t runnable_avg, usage_avg;
> #endif
>
> #ifdef CONFIG_RT_GROUP_SCHED
> @@ -236,7 +236,7 @@ struct cfs_rq {
> u64 last_decay;
>
> #ifdef CONFIG_FAIR_GROUP_SCHED
> - u32 tg_runnable_contrib;
> + u32 tg_runnable_contrib, tg_usage_contrib;
> u64 tg_load_contrib;
> #endif /* CONFIG_FAIR_GROUP_SCHED */
>
>
>
--
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