Here is the 2nd version of the cpuacct statistics patch. Copying linux-arch list also this time to check if archs which define CONFIG_VIRT_CPU_ACCOUNTING are ok with this change. Changes for v2: - stime and utime now exported in clock_t units instead of msecs. - Addressed the code review comments from Balbir and Li Zefan. - Moved to -tip tree. v1: - http://lkml.org/lkml/2009/3/10/150 cpuacct: Add stime and utime statistics Add per-cgroup cpuacct controller statistics like the system and user time consumed by the group of tasks. Signed-off-by: Bharata B Rao <bharata@xxxxxxxxxxxxxxxxxx> Signed-off-by: Balaji Rao <balajirrao@xxxxxxxxx> --- Documentation/cgroups/cpuacct.txt | 17 +++++++ kernel/sched.c | 86 +++++++++++++++++++++++++++++++++++--- 2 files changed, 97 insertions(+), 6 deletions(-) --- a/Documentation/cgroups/cpuacct.txt +++ b/Documentation/cgroups/cpuacct.txt @@ -30,3 +30,20 @@ The above steps create a new group g1 an process (bash) into it. CPU time consumed by this bash and its children can be obtained from g1/cpuacct.usage and the same is accumulated in /cgroups/cpuacct.usage also. + +cpuacct.stat file lists a few statistics which further divide the +CPU time obtained by the cgroup into user and system times. Currently +the following statistics are supported: + +utime: Time spent by tasks of the cgroup in user mode. +stime: Time spent by tasks of the cgroup in kernel mode. + +utime and stime are in USER_HZ unit. + +cpuacct controller uses percpu_counter interface to collect utime and +stime. This causes two side effects: + +- It is theoritically possible to see wrong values for stime and utime. + This is because percpu_counter_read() on 32bit systems is broken. +- It is possible to see slightly outdated values for stime and utime + due to the batch processing nature of percpu_counter. --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1434,10 +1434,22 @@ iter_move_one_task(struct rq *this_rq, i struct rq_iterator *iterator); #endif +/* Time spent by the tasks of the cpu accounting group executing in ... */ +enum cpuacct_stat_index { + CPUACCT_STAT_UTIME, /* ... user mode */ + CPUACCT_STAT_STIME, /* ... kernel mode */ + + CPUACCT_STAT_NSTATS, +}; + #ifdef CONFIG_CGROUP_CPUACCT static void cpuacct_charge(struct task_struct *tsk, u64 cputime); +static void cpuacct_update_stats(struct task_struct *tsk, + enum cpuacct_stat_index idx, cputime_t val); #else static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} +static void cpuacct_update_stats(struct task_struct *tsk, + enum cpuacct_stat_index idx, cputime_t val) {} #endif static inline void inc_cpu_load(struct rq *rq, unsigned long load) @@ -4379,6 +4391,8 @@ void account_user_time(struct task_struc cpustat->nice = cputime64_add(cpustat->nice, tmp); else cpustat->user = cputime64_add(cpustat->user, tmp); + + cpuacct_update_stats(p, CPUACCT_STAT_UTIME, cputime); /* Account for user time used */ acct_update_integrals(p); } @@ -4440,6 +4454,8 @@ void account_system_time(struct task_str else cpustat->system = cputime64_add(cpustat->system, tmp); + cpuacct_update_stats(p, CPUACCT_STAT_STIME, cputime); + /* Account for system time used */ acct_update_integrals(p); } @@ -9723,6 +9739,7 @@ struct cpuacct { struct cgroup_subsys_state css; /* cpuusage holds pointer to a u64-type object on every cpu */ u64 *cpuusage; + struct percpu_counter cpustat[CPUACCT_STAT_NSTATS]; struct cpuacct *parent; }; @@ -9747,20 +9764,33 @@ static struct cgroup_subsys_state *cpuac struct cgroup_subsys *ss, struct cgroup *cgrp) { struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); + int i; if (!ca) - return ERR_PTR(-ENOMEM); + goto out; ca->cpuusage = alloc_percpu(u64); - if (!ca->cpuusage) { - kfree(ca); - return ERR_PTR(-ENOMEM); - } + if (!ca->cpuusage) + goto out_free_ca; + + for (i = 0; i < CPUACCT_STAT_NSTATS; i++) + if (percpu_counter_init(&ca->cpustat[i], 0)) + goto out_free_counters; if (cgrp->parent) ca->parent = cgroup_ca(cgrp->parent); return &ca->css; + +out_free_counters: + i--; + while (i-- >= 0) + percpu_counter_destroy(&ca->cpustat[i]); + free_percpu(ca->cpuusage); +out_free_ca: + kfree(ca); +out: + return ERR_PTR(-ENOMEM); } /* destroy an existing cpu accounting group */ @@ -9768,7 +9798,10 @@ static void cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) { struct cpuacct *ca = cgroup_ca(cgrp); + int i; + for (i = 0; i < CPUACCT_STAT_NSTATS; i++) + percpu_counter_destroy(&ca->cpustat[i]); free_percpu(ca->cpuusage); kfree(ca); } @@ -9855,6 +9888,25 @@ static int cpuacct_percpu_seq_read(struc return 0; } +static const char *cpuacct_stat_desc[] = { + [CPUACCT_STAT_UTIME] = "utime", + [CPUACCT_STAT_STIME] = "stime", +}; + +static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, + struct cgroup_map_cb *cb) +{ + struct cpuacct *ca = cgroup_ca(cgrp); + int i; + + for (i = 0; i < CPUACCT_STAT_NSTATS; i++) { + s64 val = percpu_counter_read(&ca->cpustat[i]); + val = cputime_to_clock_t(val); + cb->fill(cb, cpuacct_stat_desc[i], val); + } + return 0; +} + static struct cftype files[] = { { .name = "usage", @@ -9865,7 +9917,10 @@ static struct cftype files[] = { .name = "usage_percpu", .read_seq_string = cpuacct_percpu_seq_read, }, - + { + .name = "stat", + .read_map = cpuacct_stats_show, + }, }; static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) @@ -9895,6 +9950,25 @@ static void cpuacct_charge(struct task_s } } +/* + * Account the system/user time to the task's accounting group. + */ +static void cpuacct_update_stats(struct task_struct *tsk, + enum cpuacct_stat_index idx, cputime_t val) +{ + struct cpuacct *ca; + + if (unlikely(!cpuacct_subsys.active)) + return; + + ca = task_ca(tsk); + + do { + percpu_counter_add(&ca->cpustat[idx], val); + ca = ca->parent; + } while (ca); +} + struct cgroup_subsys cpuacct_subsys = { .name = "cpuacct", .create = cpuacct_create, -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
