Messages in this thread | | | Date | Tue, 13 Mar 2012 17:57:52 +0100 | Subject | Re: [RFC PATCH 14/14] sched: implement usage tracking | From | Vincent Guittot <> |
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Hi Paul,
On 2 February 2012 02:38, Paul Turner <pjt@google.com> wrote: > 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@google.com> > Signed-off-by: Ben Segall <bsegall@google.com> > --- > include/linux/sched.h | 1 + > kernel/sched/debug.c | 3 +++ > kernel/sched/fair.c | 29 +++++++++++++++++++++++------ > kernel/sched/sched.h | 4 ++-- > 4 files changed, 29 insertions(+), 8 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 09b8c45..209185f 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1159,6 +1159,7 @@ struct load_weight { > struct sched_avg { > u64 runnable_avg_sum, runnable_avg_period; > u64 last_runnable_update, decay_count; > + u32 usage_avg_sum;
Why usage_avg_sum is 32bits whereas runnable_avg_sum and runnable_avg_period are 64bits long ? You are doing the same computation on these 3 variables. Only the computation need to be done in 64bits but the result could be saved in 32bits ?
Regards, Vincent
> unsigned long load_avg_contrib; > > int contributes_blocked_load; > diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c > index 0911ec6..4d39069 100644 > --- a/kernel/sched/debug.c > +++ b/kernel/sched/debug.c > @@ -93,6 +93,7 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group > P(se->load.weight); > 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); > #undef PN > @@ -228,6 +229,8 @@ 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 ad524bb..222c2c9 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -997,7 +997,8 @@ static u32 __compute_runnable_contrib(int n) > */ > static __always_inline int __update_entity_runnable_avg(u64 now, > struct sched_avg *sa, > - int runnable) > + int runnable, > + int running) > { > u64 delta; > u32 periods, runnable_contrib; > @@ -1026,6 +1027,8 @@ 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; > @@ -1036,15 +1039,20 @@ 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); > > 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; > } > > if (runnable) > sa->runnable_avg_sum += delta; > + if (running) > + sa->usage_avg_sum += delta; > sa->runnable_avg_period += delta; > > return decayed; > @@ -1081,14 +1089,21 @@ 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; > > contrib = (sa->runnable_avg_sum << 12) / (sa->runnable_avg_period + 1); > contrib -= cfs_rq->tg_runnable_contrib; > > - if (abs(contrib) > cfs_rq->tg_runnable_contrib/64) { > + usage_contrib = (sa->usage_avg_sum << 12) / (sa->runnable_avg_period + 1); > + usage_contrib -= cfs_rq->tg_usage_contrib; > + > + 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; > } > } > > @@ -1164,8 +1179,8 @@ static inline void update_entity_load_avg(struct sched_entity *se, > struct cfs_rq *cfs_rq = cfs_rq_of(se); > long contrib_delta; > > - if(!__update_entity_runnable_avg(rq_of(cfs_rq)->clock_task, &se->avg, > - se->on_rq)) > + if(!__update_entity_runnable_avg(cfs_rq_clock_task(cfs_rq), &se->avg, > + se->on_rq, cfs_rq->curr == se)) > return; > > contrib_delta = __update_entity_load_avg_contrib(se); > @@ -1210,7 +1225,8 @@ 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); > } > > @@ -1590,6 +1606,7 @@ 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 77f3297..9602a47 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -117,7 +117,7 @@ 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 > @@ -260,7 +260,7 @@ struct cfs_rq { > */ > unsigned long h_load; > > - u32 tg_runnable_contrib; > + u32 tg_runnable_contrib, tg_usage_contrib; > u64 runnable_load_avg, blocked_load_avg; > u64 tg_load_contrib; > atomic64_t decay_counter, removed_load; > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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