Messages in this thread Patch in this message | | | From | Balaji Rao <> | Subject | [RFC][-mm] Simple stats for cpu resource controller v3 | Date | Thu, 1 May 2008 23:11:06 +0530 |
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This implements a couple of basic statistics for the CPU resource controller.
v2->v3 ------- Proper locking while collecting stats. Thanks to Peter Zijlstra for suggesting the delta approach.
This applies against 2.6.25-mm1 ---
Signed-off-by: Balaji Rao <balajirrao@gmail.com>
diff --git a/kernel/sched.c b/kernel/sched.c index bbdc32a..5bda75a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -248,10 +248,51 @@ struct cfs_rq; static LIST_HEAD(task_groups); +#ifdef CONFIG_CGROUP_SCHED + +#define CPU_CGROUP_STAT_THRESHOLD 1 << 30 + +enum cpu_cgroup_stat_index { + CPU_CGROUP_STAT_UTIME, /* Usertime of the task group */ + CPU_CGROUP_STAT_STIME, /* Kerneltime of the task group */ + + CPU_CGROUP_STAT_NSTATS, +}; + +struct cpu_cgroup_stat_cpu { + s64 count[CPU_CGROUP_STAT_NSTATS]; + u32 delta[CPU_CGROUP_STAT_NSTATS]; +} ____cacheline_aligned_in_smp; + +struct cpu_cgroup_stat { + struct cpu_cgroup_stat_cpu cpustat[NR_CPUS]; + spinlock_t lock; +}; + +/* Called under irq disable. */ +static void __cpu_cgroup_stat_add(struct cpu_cgroup_stat *stat, + enum cpu_cgroup_stat_index idx, int val) +{ + int cpu = smp_processor_id(); + unsigned long flags; + + BUG_ON(!irqs_disabled()); + stat->cpustat[cpu].delta[idx] += val; + + if (stat->cpustat[cpu].delta[idx] > CPU_CGROUP_STAT_THRESHOLD) { + spin_lock_irqsave(&stat->lock, flags); + stat->cpustat[cpu].count[idx] += stat->cpustat[cpu].delta[idx]; + stat->cpustat[cpu].delta[idx] = 0; + spin_unlock_irqrestore(&stat->lock, flags); + } +} +#endif + /* task group related information */ struct task_group { #ifdef CONFIG_CGROUP_SCHED struct cgroup_subsys_state css; + struct cpu_cgroup_stat stat; #endif #ifdef CONFIG_FAIR_GROUP_SCHED @@ -3837,6 +3878,16 @@ void account_user_time(struct task_struct *p, cputime_t cputime) cpustat->nice = cputime64_add(cpustat->nice, tmp); else cpustat->user = cputime64_add(cpustat->user, tmp); + + /* Charge the task's group */ +#ifdef CONFIG_CGROUP_SCHED + { + struct task_group *tg; + tg = task_group(p); + __cpu_cgroup_stat_add(&tg->stat, CPU_CGROUP_STAT_UTIME, + cputime_to_msecs(cputime)); + } +#endif } /* @@ -3900,6 +3951,15 @@ void account_system_time(struct task_struct *p, int hardirq_offset, cpustat->idle = cputime64_add(cpustat->idle, tmp); /* Account for system time used */ acct_update_integrals(p); + +#ifdef CONFIG_CGROUP_SCHED + { + struct task_group *tg; + tg = task_group(p); + __cpu_cgroup_stat_add(&tg->stat, CPU_CGROUP_STAT_STIME, + cputime_to_msecs(cputime)); + } +#endif } /* @@ -7838,7 +7898,9 @@ struct task_group *sched_create_group(void) } list_add_rcu(&tg->list, &task_groups); spin_unlock_irqrestore(&task_group_lock, flags); - +#ifdef CONFIG_CGROUP_SCHED + spin_lock_init(&tg->stat.lock); +#endif return tg; err: @@ -8249,6 +8311,48 @@ static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) return (u64) tg->shares; } + +static s64 cpu_cgroup_read_stat(struct cpu_cgroup_stat *stat, + enum cpu_cgroup_stat_index idx) +{ + int cpu; + s64 ret = 0; + unsigned long flags; + + spin_lock_irqsave(&stat->lock, flags); + for_each_possible_cpu(cpu) { + stat->cpustat[cpu].count[idx] += stat->cpustat[cpu].delta[idx]; + stat->cpustat[cpu].delta[idx] = 0; + ret += stat->cpustat[cpu].count[idx]; + } + spin_unlock_irqrestore(&stat->lock, flags); + + return ret; +} + +static const struct cpu_cgroup_stat_desc { + const char *msg; + u64 unit; +} cpu_cgroup_stat_desc[] = { + [CPU_CGROUP_STAT_UTIME] = { "utime", 1, }, + [CPU_CGROUP_STAT_STIME] = { "stime", 1, }, +}; + +static int cpu_cgroup_stats_show(struct cgroup *cgrp, struct cftype *cft, + struct cgroup_map_cb *cb) +{ + struct task_group *tg = cgroup_tg(cgrp); + struct cpu_cgroup_stat *stat = &tg->stat; + int i; + + for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) { + s64 val; + val = cpu_cgroup_read_stat(stat, i); + val *= cpu_cgroup_stat_desc[i].unit; + cb->fill(cb, cpu_cgroup_stat_desc[i].msg, val); + } + return 0; +} #endif #ifdef CONFIG_RT_GROUP_SCHED @@ -8295,6 +8399,10 @@ static struct cftype cpu_files[] = { .write_u64 = cpu_rt_period_write_uint, }, #endif + { + .name = "stat", + .read_map = cpu_cgroup_stats_show, + }, }; static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) -- Warm Regards,
Balaji Rao Dept. of Mechanical Engineering NITK
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