Re: [PATCH] Group scheduler statistics in one struct
From: Lucas De Marchi
Date: Wed Mar 10 2010 - 21:30:02 EST
On Wed, Mar 10, 2010 at 02:18, Lucas De Marchi
<lucas.de.marchi@xxxxxxxxx> wrote:
> On Wed, Mar 10, 2010 at 02:07, Lucas De Marchi
> <lucas.de.marchi@xxxxxxxxx> wrote:
>>
>> From: Lucas De Marchi <lucas.de.marchi@xxxxxxxxx>
>>
>> Put all statistic fields of sched_entity in one struct, sched_statistics,
>> and embed it into sched_entity.
>>
>> This change allows to memset the sched_statistics to 0 when needed (for
>> instance when forking), avoiding bugs of non initialized fields.
>>
>> Signed-off-by: Lucas De Marchi <lucas.de.marchi@xxxxxxxxx>
>> ---
>> include/linux/sched.h | 54 ++++++++++++--------------
>> kernel/sched.c | 47 ++++------------------
>> kernel/sched_debug.c | 101 ++++++++++++++++++------------------------------
>> kernel/sched_fair.c | 65 ++++++++++++++++---------------
>> kernel/sched_rt.c | 2 +-
>> 5 files changed, 106 insertions(+), 163 deletions(-)
>>
>
> This patch is sitting on my .31's tree for quite a time. Today on
> checking out .34 I've seen there were new fields introduced by
> 8f0dfc34 "sched: Provide iowait counters" that were not properly
> initialized upon task fork ( __sched_fork()). Since this is not the
> first time this happens with these fields, I think it's better to use
> an approach like the patch below.
>
>
And of course this does not work because it has a typo and I forgot to
test with SCHED_DEBUG enabled. I'm sending the right version in a
following email.
Lucas De Marchi
>
>> diff --git a/include/linux/sched.h b/include/linux/sched.h
>> index 46c6f8d..909e630 100644
>> --- a/include/linux/sched.h
>> +++ b/include/linux/sched.h
>> @@ -1073,36 +1073,8 @@ struct load_weight {
>> unsigned long weight, inv_weight;
>> };
>>
>> -/*
>> - * CFS stats for a schedulable entity (task, task-group etc)
>> - *
>> - * Current field usage histogram:
>> - *
>> - * 4 se->block_start
>> - * 4 se->run_node
>> - * 4 se->sleep_start
>> - * 6 se->load.weight
>> - */
>> -struct sched_entity {
>> - struct load_weight load; /* for load-balancing */
>> - struct rb_node run_node;
>> - struct list_head group_node;
>> - unsigned int on_rq;
>> -
>> - u64 exec_start;
>> - u64 sum_exec_runtime;
>> - u64 vruntime;
>> - u64 prev_sum_exec_runtime;
>> -
>> - u64 last_wakeup;
>> - u64 avg_overlap;
>> -
>> - u64 nr_migrations;
>> -
>> - u64 start_runtime;
>> - u64 avg_wakeup;
>> -
>> #ifdef CONFIG_SCHEDSTATS
>> +struct sched_statistics {
>> u64 wait_start;
>> u64 wait_max;
>> u64 wait_count;
>> @@ -1134,6 +1106,30 @@ struct sched_entity {
>> u64 nr_wakeups_affine_attempts;
>> u64 nr_wakeups_passive;
>> u64 nr_wakeups_idle;
>> +};
>> +#endif
>> +
>> +struct sched_entity {
>> + struct load_weight load; /* for load-balancing */
>> + struct rb_node run_node;
>> + struct list_head group_node;
>> + unsigned int on_rq;
>> +
>> + u64 exec_start;
>> + u64 sum_exec_runtime;
>> + u64 vruntime;
>> + u64 prev_sum_exec_runtime;
>> +
>> + u64 last_wakeup;
>> + u64 avg_overlap;
>> +
>> + u64 nr_migrations;
>> +
>> + u64 start_runtime;
>> + u64 avg_wakeup;
>> +
>> +#ifdef CONFIG_SCHEDSTATS
>> + struct sched_statistics statistics;
>> #endif
>>
>> #ifdef CONFIG_FAIR_GROUP_SCHED
>> diff --git a/kernel/sched.c b/kernel/sched.c
>> index 150b698..35c6b8a 100644
>> --- a/kernel/sched.c
>> +++ b/kernel/sched.c
>> @@ -2437,15 +2437,15 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
>>
>> out_activate:
>> #endif /* CONFIG_SMP */
>> - schedstat_inc(p, se.nr_wakeups);
>> + schedstat_inc(p, se.statistics.nr_wakeups);
>> if (wake_flags & WF_SYNC)
>> - schedstat_inc(p, se.nr_wakeups_sync);
>> + schedstat_inc(p, se.statistics.nr_wakeups_sync);
>> if (orig_cpu != cpu)
>> - schedstat_inc(p, se.nr_wakeups_migrate);
>> + schedstat_inc(p, se.statistics.nr_wakeups_migrate);
>> if (cpu == this_cpu)
>> - schedstat_inc(p, se.nr_wakeups_local);
>> + schedstat_inc(p, se.statistics.nr_wakeups_local);
>> else
>> - schedstat_inc(p, se.nr_wakeups_remote);
>> + schedstat_inc(p, se.statistics.nr_wakeups_remote);
>> activate_task(rq, p, 1);
>> success = 1;
>>
>> @@ -2532,36 +2532,7 @@ static void __sched_fork(struct task_struct *p)
>> p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
>>
>> #ifdef CONFIG_SCHEDSTATS
>> - p->se.wait_start = 0;
>> - p->se.wait_max = 0;
>> - p->se.wait_count = 0;
>> - p->se.wait_sum = 0;
>> -
>> - p->se.sleep_start = 0;
>> - p->se.sleep_max = 0;
>> - p->se.sum_sleep_runtime = 0;
>> -
>> - p->se.block_start = 0;
>> - p->se.block_max = 0;
>> - p->se.exec_max = 0;
>> - p->se.slice_max = 0;
>> -
>> - p->se.nr_migrations_cold = 0;
>> - p->se.nr_failed_migrations_affine = 0;
>> - p->se.nr_failed_migrations_running = 0;
>> - p->se.nr_failed_migrations_hot = 0;
>> - p->se.nr_forced_migrations = 0;
>> -
>> - p->se.nr_wakeups = 0;
>> - p->se.nr_wakeups_sync = 0;
>> - p->se.nr_wakeups_migrate = 0;
>> - p->se.nr_wakeups_local = 0;
>> - p->se.nr_wakeups_remote = 0;
>> - p->se.nr_wakeups_affine = 0;
>> - p->se.nr_wakeups_affine_attempts = 0;
>> - p->se.nr_wakeups_passive = 0;
>> - p->se.nr_wakeups_idle = 0;
>> -
>> + memset(&p->se.statistics, 0, sizeof(p->se.statistics));
>> #endif
>>
>> INIT_LIST_HEAD(&p->rt.run_list);
>> @@ -7914,9 +7885,9 @@ void normalize_rt_tasks(void)
>>
>> p->se.exec_start = 0;
>> #ifdef CONFIG_SCHEDSTATS
>> - p->se.wait_start = 0;
>> - p->se.sleep_start = 0;
>> - p->se.block_start = 0;
>> + p->se.statistics.wait_start = 0;
>> + p->se.statistics.sleep_start = 0;
>> + p->se.statistics.block_start = 0;
>> #endif
>>
>> if (!rt_task(p)) {
>> diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
>> index 67f95aa..f6e8ed6 100644
>> --- a/kernel/sched_debug.c
>> +++ b/kernel/sched_debug.c
>> @@ -70,16 +70,16 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu,
>> PN(se->vruntime);
>> PN(se->sum_exec_runtime);
>> #ifdef CONFIG_SCHEDSTATS
>> - PN(se->wait_start);
>> - PN(se->sleep_start);
>> - PN(se->block_start);
>> - PN(se->sleep_max);
>> - PN(se->block_max);
>> - PN(se->exec_max);
>> - PN(se->slice_max);
>> - PN(se->wait_max);
>> - PN(se->wait_sum);
>> - P(se->wait_count);
>> + PN(se->statistiscs.wait_start);
>> + PN(se->statistiscs.sleep_start);
>> + PN(se->statistiscs.block_start);
>> + PN(se->statistiscs.sleep_max);
>> + PN(se->statistiscs.block_max);
>> + PN(se->statistiscs.exec_max);
>> + PN(se->statistiscs.slice_max);
>> + PN(se->statistiscs.wait_max);
>> + PN(se->statistiscs.wait_sum);
>> + P(se->statistiscs.wait_count);
>> #endif
>> P(se->load.weight);
>> #undef PN
>> @@ -104,7 +104,7 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
>> SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld",
>> SPLIT_NS(p->se.vruntime),
>> SPLIT_NS(p->se.sum_exec_runtime),
>> - SPLIT_NS(p->se.sum_sleep_runtime));
>> + SPLIT_NS(p->se.statistics.sum_sleep_runtime));
>> #else
>> SEQ_printf(m, "%15Ld %15Ld %15Ld.%06ld %15Ld.%06ld %15Ld.%06ld",
>> 0LL, 0LL, 0LL, 0L, 0LL, 0L, 0LL, 0L);
>> @@ -413,34 +413,34 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
>> nr_switches = p->nvcsw + p->nivcsw;
>>
>> #ifdef CONFIG_SCHEDSTATS
>> - PN(se.wait_start);
>> - PN(se.sleep_start);
>> - PN(se.block_start);
>> - PN(se.sleep_max);
>> - PN(se.block_max);
>> - PN(se.exec_max);
>> - PN(se.slice_max);
>> - PN(se.wait_max);
>> - PN(se.wait_sum);
>> - P(se.wait_count);
>> - PN(se.iowait_sum);
>> - P(se.iowait_count);
>> + PN(se.statistiscs.wait_start);
>> + PN(se.statistiscs.sleep_start);
>> + PN(se.statistiscs.block_start);
>> + PN(se.statistiscs.sleep_max);
>> + PN(se.statistiscs.block_max);
>> + PN(se.statistiscs.exec_max);
>> + PN(se.statistiscs.slice_max);
>> + PN(se.statistiscs.wait_max);
>> + PN(se.statistiscs.wait_sum);
>> + P(se.statistiscs.wait_count);
>> + PN(se.statistiscs.iowait_sum);
>> + P(se.statistiscs.iowait_count);
>> P(sched_info.bkl_count);
>> P(se.nr_migrations);
>> - P(se.nr_migrations_cold);
>> - P(se.nr_failed_migrations_affine);
>> - P(se.nr_failed_migrations_running);
>> - P(se.nr_failed_migrations_hot);
>> - P(se.nr_forced_migrations);
>> - P(se.nr_wakeups);
>> - P(se.nr_wakeups_sync);
>> - P(se.nr_wakeups_migrate);
>> - P(se.nr_wakeups_local);
>> - P(se.nr_wakeups_remote);
>> - P(se.nr_wakeups_affine);
>> - P(se.nr_wakeups_affine_attempts);
>> - P(se.nr_wakeups_passive);
>> - P(se.nr_wakeups_idle);
>> + P(se.statistiscs.nr_migrations_cold);
>> + P(se.statistiscs.nr_failed_migrations_affine);
>> + P(se.statistiscs.nr_failed_migrations_running);
>> + P(se.statistiscs.nr_failed_migrations_hot);
>> + P(se.statistiscs.nr_forced_migrations);
>> + P(se.statistiscs.nr_wakeups);
>> + P(se.statistiscs.nr_wakeups_sync);
>> + P(se.statistiscs.nr_wakeups_migrate);
>> + P(se.statistiscs.nr_wakeups_local);
>> + P(se.statistiscs.nr_wakeups_remote);
>> + P(se.statistiscs.nr_wakeups_affine);
>> + P(se.statistiscs.nr_wakeups_affine_attempts);
>> + P(se.statistiscs.nr_wakeups_passive);
>> + P(se.statistiscs.nr_wakeups_idle);
>>
>> {
>> u64 avg_atom, avg_per_cpu;
>> @@ -491,32 +491,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
>> void proc_sched_set_task(struct task_struct *p)
>> {
>> #ifdef CONFIG_SCHEDSTATS
>> - p->se.wait_max = 0;
>> - p->se.wait_sum = 0;
>> - p->se.wait_count = 0;
>> - p->se.iowait_sum = 0;
>> - p->se.iowait_count = 0;
>> - p->se.sleep_max = 0;
>> - p->se.sum_sleep_runtime = 0;
>> - p->se.block_max = 0;
>> - p->se.exec_max = 0;
>> - p->se.slice_max = 0;
>> - p->se.nr_migrations = 0;
>> - p->se.nr_migrations_cold = 0;
>> - p->se.nr_failed_migrations_affine = 0;
>> - p->se.nr_failed_migrations_running = 0;
>> - p->se.nr_failed_migrations_hot = 0;
>> - p->se.nr_forced_migrations = 0;
>> - p->se.nr_wakeups = 0;
>> - p->se.nr_wakeups_sync = 0;
>> - p->se.nr_wakeups_migrate = 0;
>> - p->se.nr_wakeups_local = 0;
>> - p->se.nr_wakeups_remote = 0;
>> - p->se.nr_wakeups_affine = 0;
>> - p->se.nr_wakeups_affine_attempts = 0;
>> - p->se.nr_wakeups_passive = 0;
>> - p->se.nr_wakeups_idle = 0;
>> - p->sched_info.bkl_count = 0;
>> + memset(&p->se.statistics, 0, sizeof(p->se.statistics));
>> #endif
>> p->se.sum_exec_runtime = 0;
>> p->se.prev_sum_exec_runtime = 0;
>> diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
>> index 3e1fd96..8ad164b 100644
>> --- a/kernel/sched_fair.c
>> +++ b/kernel/sched_fair.c
>> @@ -505,7 +505,8 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
>> {
>> unsigned long delta_exec_weighted;
>>
>> - schedstat_set(curr->exec_max, max((u64)delta_exec, curr->exec_max));
>> + schedstat_set(curr->statistics.exec_max,
>> + max((u64)delta_exec, curr->statistics.exec_max));
>>
>> curr->sum_exec_runtime += delta_exec;
>> schedstat_add(cfs_rq, exec_clock, delta_exec);
>> @@ -548,7 +549,7 @@ static void update_curr(struct cfs_rq *cfs_rq)
>> static inline void
>> update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
>> {
>> - schedstat_set(se->wait_start, rq_of(cfs_rq)->clock);
>> + schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock);
>> }
>>
>> /*
>> @@ -567,18 +568,18 @@ static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
>> static void
>> update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
>> {
>> - schedstat_set(se->wait_max, max(se->wait_max,
>> - rq_of(cfs_rq)->clock - se->wait_start));
>> - schedstat_set(se->wait_count, se->wait_count + 1);
>> - schedstat_set(se->wait_sum, se->wait_sum +
>> - rq_of(cfs_rq)->clock - se->wait_start);
>> + schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max,
>> + rq_of(cfs_rq)->clock - se->statistics.wait_start));
>> + schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1);
>> + schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum +
>> + rq_of(cfs_rq)->clock - se->statistics.wait_start);
>> #ifdef CONFIG_SCHEDSTATS
>> if (entity_is_task(se)) {
>> trace_sched_stat_wait(task_of(se),
>> - rq_of(cfs_rq)->clock - se->wait_start);
>> + rq_of(cfs_rq)->clock - se->statistics.wait_start);
>> }
>> #endif
>> - schedstat_set(se->wait_start, 0);
>> + schedstat_set(se->statistics.wait_start, 0);
>> }
>>
>> static inline void
>> @@ -657,39 +658,39 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
>> if (entity_is_task(se))
>> tsk = task_of(se);
>>
>> - if (se->sleep_start) {
>> - u64 delta = rq_of(cfs_rq)->clock - se->sleep_start;
>> + if (se->statistics.sleep_start) {
>> + u64 delta = rq_of(cfs_rq)->clock - se->statistics.sleep_start;
>>
>> if ((s64)delta < 0)
>> delta = 0;
>>
>> - if (unlikely(delta > se->sleep_max))
>> - se->sleep_max = delta;
>> + if (unlikely(delta > se->statistics.sleep_max))
>> + se->statistics.sleep_max = delta;
>>
>> - se->sleep_start = 0;
>> - se->sum_sleep_runtime += delta;
>> + se->statistics.sleep_start = 0;
>> + se->statistics.sum_sleep_runtime += delta;
>>
>> if (tsk) {
>> account_scheduler_latency(tsk, delta >> 10, 1);
>> trace_sched_stat_sleep(tsk, delta);
>> }
>> }
>> - if (se->block_start) {
>> - u64 delta = rq_of(cfs_rq)->clock - se->block_start;
>> + if (se->statistics.block_start) {
>> + u64 delta = rq_of(cfs_rq)->clock - se->statistics.block_start;
>>
>> if ((s64)delta < 0)
>> delta = 0;
>>
>> - if (unlikely(delta > se->block_max))
>> - se->block_max = delta;
>> + if (unlikely(delta > se->statistics.block_max))
>> + se->statistics.block_max = delta;
>>
>> - se->block_start = 0;
>> - se->sum_sleep_runtime += delta;
>> + se->statistics.block_start = 0;
>> + se->statistics.sum_sleep_runtime += delta;
>>
>> if (tsk) {
>> if (tsk->in_iowait) {
>> - se->iowait_sum += delta;
>> - se->iowait_count++;
>> + se->statistics.iowait_sum += delta;
>> + se->statistics.iowait_count++;
>> trace_sched_stat_iowait(tsk, delta);
>> }
>>
>> @@ -826,9 +827,9 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
>> struct task_struct *tsk = task_of(se);
>>
>> if (tsk->state & TASK_INTERRUPTIBLE)
>> - se->sleep_start = rq_of(cfs_rq)->clock;
>> + se->statistics.sleep_start = rq_of(cfs_rq)->clock;
>> if (tsk->state & TASK_UNINTERRUPTIBLE)
>> - se->block_start = rq_of(cfs_rq)->clock;
>> + se->statistics.block_start = rq_of(cfs_rq)->clock;
>> }
>> #endif
>> }
>> @@ -912,7 +913,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
>> * when there are only lesser-weight tasks around):
>> */
>> if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
>> - se->slice_max = max(se->slice_max,
>> + se->statistics.slice_max = max(se->statistics.slice_max,
>> se->sum_exec_runtime - se->prev_sum_exec_runtime);
>> }
>> #endif
>> @@ -1306,7 +1307,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
>> if (sync && balanced)
>> return 1;
>>
>> - schedstat_inc(p, se.nr_wakeups_affine_attempts);
>> + schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);
>> tl_per_task = cpu_avg_load_per_task(this_cpu);
>>
>> if (balanced ||
>> @@ -1318,7 +1319,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
>> * there is no bad imbalance.
>> */
>> schedstat_inc(sd, ttwu_move_affine);
>> - schedstat_inc(p, se.nr_wakeups_affine);
>> + schedstat_inc(p, se.statistics.nr_wakeups_affine);
>>
>> return 1;
>> }
>> @@ -1844,13 +1845,13 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
>> * 3) are cache-hot on their current CPU.
>> */
>> if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) {
>> - schedstat_inc(p, se.nr_failed_migrations_affine);
>> + schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
>> return 0;
>> }
>> *all_pinned = 0;
>>
>> if (task_running(rq, p)) {
>> - schedstat_inc(p, se.nr_failed_migrations_running);
>> + schedstat_inc(p, se.statistics.nr_failed_migrations_running);
>> return 0;
>> }
>>
>> @@ -1866,14 +1867,14 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
>> #ifdef CONFIG_SCHEDSTATS
>> if (tsk_cache_hot) {
>> schedstat_inc(sd, lb_hot_gained[idle]);
>> - schedstat_inc(p, se.nr_forced_migrations);
>> + schedstat_inc(p, se.statistics.nr_forced_migrations);
>> }
>> #endif
>> return 1;
>> }
>>
>> if (tsk_cache_hot) {
>> - schedstat_inc(p, se.nr_failed_migrations_hot);
>> + schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
>> return 0;
>> }
>> return 1;
>> diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
>> index 5a6ed1f..47a121d 100644
>> --- a/kernel/sched_rt.c
>> +++ b/kernel/sched_rt.c
>> @@ -613,7 +613,7 @@ static void update_curr_rt(struct rq *rq)
>> if (unlikely((s64)delta_exec < 0))
>> delta_exec = 0;
>>
>> - schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec));
>> + schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec));
>>
>> curr->se.sum_exec_runtime += delta_exec;
>> account_group_exec_runtime(curr, delta_exec);
>> --
>> 1.7.0.2
>>
>
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