The file cpu.stat_percpu will show various scheduler related information, that are usually available to the top level through other files.
For instance, most of the meaningful data in /proc/stat is presented here. Given this file, a container can easily construct a local copy of /proc/stat for internal consumption. The data we export is comprised of: * all the tick information, previously available only through cpuacct, like user time, system time, etc. * wait time, which can be used to construct analogous information to steal time in hypervisors, * nr_switches and nr_running, which are cgroup-local versions of their global counterparts. The file includes a header, so fields can come and go if needed. Signed-off-by: Glauber Costa <[email protected]> CC: Peter Zijlstra <[email protected]> CC: Paul Turner <[email protected]> --- kernel/sched/core.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/sched/fair.c | 13 +++++++ kernel/sched/sched.h | 1 + 3 files changed, 111 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6bb56f0..5135b50 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8111,6 +8111,97 @@ static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) } #endif /* CONFIG_RT_GROUP_SCHED */ +#ifdef CONFIG_SCHEDSTATS + +#ifdef CONFIG_FAIR_GROUP_SCHED +#define fair_rq(field, tg, i) (tg)->cfs_rq[i]->field +#else +#define fair_rq(field, tg, i) 0 +#endif + +#ifdef CONFIG_RT_GROUP_SCHED +#define rt_rq(field, tg, i) (tg)->rt_rq[i]->field +#else +#define rt_rq(field, tg, i) 0 +#endif + +static u64 tg_nr_switches(struct task_group *tg, int cpu) +{ + /* nr_switches, which counts idle and stop task, is added to all tgs */ + return cpu_rq(cpu)->nr_switches + + cfs_nr_switches(tg, cpu) + rt_nr_switches(tg, cpu); +} + +static u64 tg_nr_running(struct task_group *tg, int cpu) +{ + /* + * because of autogrouped groups in root_task_group, the + * following does not hold. + */ + if (tg != &root_task_group) + return rt_rq(rt_nr_running, tg, cpu) + fair_rq(nr_running, tg, cpu); + + return cpu_rq(cpu)->nr_running; +} + +static u64 tg_wait(struct task_group *tg, int cpu) +{ + u64 val; + + if (tg != &root_task_group) + val = cfs_read_wait(tg->se[cpu]); + else + /* + * There are many errors here that we are accumulating. + * However, we only provide this in the interest of having + * a consistent interface for all cgroups. Everybody + * probing the root cgroup should be getting its figures + * from system-wide files as /proc/stat. That would be faster + * to begin with... + */ + val = kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL] * TICK_NSEC; + + return val; +} + +static inline void do_fill_seq(struct seq_file *m, struct task_group *tg, + int cpu, int index) +{ + u64 val = 0; + struct kernel_cpustat *kcpustat; + kcpustat = this_cpu_ptr(tg->cpustat); + val = cputime64_to_clock_t(kcpustat->cpustat[index]) * TICK_NSEC; + seq_put_decimal_ull(m, ' ', val); +} + +static int cpu_stats_percpu_show(struct cgroup *cgrp, struct cftype *cft, + struct seq_file *m) +{ + struct task_group *tg = cgroup_tg(cgrp); + int cpu; + + seq_printf(m, "user nice system irq softirq guest guest_nice "); + seq_printf(m, "wait nr_switches nr_running\n"); + + for_each_online_cpu(cpu) { + seq_printf(m, "cpu%d", cpu); + do_fill_seq(m, tg, cpu, CPUTIME_USER); + do_fill_seq(m, tg, cpu, CPUTIME_NICE); + do_fill_seq(m, tg, cpu, CPUTIME_SYSTEM); + do_fill_seq(m, tg, cpu, CPUTIME_IRQ); + do_fill_seq(m, tg, cpu, CPUTIME_SOFTIRQ); + do_fill_seq(m, tg, cpu, CPUTIME_GUEST); + do_fill_seq(m, tg, cpu, CPUTIME_GUEST_NICE); + seq_put_decimal_ull(m, ' ', tg_wait(tg, cpu)); + seq_put_decimal_ull(m, ' ', tg_nr_switches(tg, cpu)); + seq_put_decimal_ull(m, ' ', tg_nr_running(tg, cpu)); + seq_putc(m, '\n'); + } + + return 0; +} +#endif + static struct cftype cpu_files[] = { #ifdef CONFIG_FAIR_GROUP_SCHED { @@ -8164,6 +8255,12 @@ static struct cftype cpu_files[] = { .flags = CFTYPE_NO_PREFIX, .read_map = cpucg_stats_show, }, +#ifdef CONFIG_SCHEDSTATS + { + .name = "stat_percpu", + .read_seq_string = cpu_stats_percpu_show, + }, +#endif { } /* terminate */ }; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0dd9c50..778b249 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -721,6 +721,19 @@ update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock); } +#ifdef CONFIG_SCHEDSTATS +u64 cfs_read_wait(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = cfs_rq_of(se); + u64 value = se->statistics.wait_sum; + + if (!se->statistics.wait_start) + return value; + + return value + rq_of(cfs_rq)->clock - se->statistics.wait_start; +} +#endif + /* * Task is being enqueued - update stats: */ diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index a426abc..0a12980 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1195,6 +1195,7 @@ extern void init_cfs_rq(struct cfs_rq *cfs_rq); extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq); extern void account_cfs_bandwidth_used(int enabled, int was_enabled); +extern u64 cfs_read_wait(struct sched_entity *se); #ifdef CONFIG_NO_HZ enum rq_nohz_flag_bits { -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
