Messages in this thread Patch in this message | | | Date | Tue, 10 Mar 2009 18:12:08 +0530 | From | Bharata B Rao <> | Subject | [RFC PATCH] cpuacct: per-cgroup utime/stime statistics - v1 |
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Hi,
Based on the comments received during my last post (http://lkml.org/lkml/2009/2/25/129), here is a fresh attempt to get per-cgroup utime/stime statistics as part of cpuacct controller.
This patch adds a new file cpuacct.stat which displays two stats: utime and stime. I wasn't too sure about the usefulness of providing per-cgroup guest and steal times and hence not including them here.
Note that I am using percpu_counter for collecting these two stats. Since percpu_counter subsystem doesn't protect the readside, readers could theoritically obtain incorrect values for these stats on 32bit systems. I hope occasional wrong values is not too much of a concern for statistics like this. If it is a problem, we have to either fix percpu_counter or do it all by ourselves as Kamezawa attempted for cpuacct.usage (http://lkml.org/lkml/2009/3/4/14)
Regards, Bharata.
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@linux.vnet.ibm.com> Signed-off-by: Balaji Rao <balajirrao@gmail.com> --- Documentation/cgroups/cpuacct.txt | 8 +++ kernel/sched.c | 87 +++++++++++++++++++++++++++++++++++--- 2 files changed, 89 insertions(+), 6 deletions(-)
--- a/Documentation/cgroups/cpuacct.txt +++ b/Documentation/cgroups/cpuacct.txt @@ -30,3 +30,11 @@ 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 in milliseconds spent by tasks of the cgroup in user mode. +stime: Time in milliseconds spent by tasks of the cgroup in kernel mode. + --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1393,10 +1393,22 @@ 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, int 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, int val) {} #endif static inline void inc_cpu_load(struct rq *rq, unsigned long load) @@ -4182,6 +4194,8 @@ 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_to_msecs(cputime)); /* Account for user time used */ acct_update_integrals(p); } @@ -4243,6 +4257,8 @@ void account_system_time(struct task_str else cpustat->system = cputime64_add(cpustat->system, tmp); + cpuacct_update_stats(p, CPUACCT_STAT_STIME, cputime_to_msecs(cputime)); + /* Account for system time used */ acct_update_integrals(p); } @@ -9438,6 +9454,7 @@ 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; }; @@ -9462,20 +9479,33 @@ 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 out1; ca->cpuusage = alloc_percpu(u64); - if (!ca->cpuusage) { - kfree(ca); - return ERR_PTR(-ENOMEM); - } + if (!ca->cpuusage) + goto out2; + + for (i = 0; i < CPUACCT_STAT_NSTATS; i++) + if (percpu_counter_init(&ca->cpustat[i], 0)) + goto out3; if (cgrp->parent) ca->parent = cgroup_ca(cgrp->parent); return &ca->css; + +out3: + i--; + while (i-- >= 0) + percpu_counter_destroy(&ca->cpustat[i]); + free_percpu(ca->cpuusage); +out2: + kfree(ca); +out1: + return ERR_PTR(-ENOMEM); } /* destroy an existing cpu accounting group */ @@ -9483,7 +9513,10 @@ 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); } @@ -9570,6 +9603,28 @@ static int cpuacct_percpu_seq_read(struc return 0; } +static const struct cpuacct_stat_desc { + const char *msg; + u64 unit; +} cpuacct_stat_desc[] = { + [CPUACCT_STAT_UTIME] = { "utime", 1, }, + [CPUACCT_STAT_STIME] = { "stime", 1, }, +}; + +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 *= cpuacct_stat_desc[i].unit; + cb->fill(cb, cpuacct_stat_desc[i].msg, val); + } + return 0; +} + static struct cftype files[] = { { .name = "usage", @@ -9580,7 +9635,10 @@ 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) @@ -9610,6 +9668,23 @@ 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, int val) +{ + struct cpuacct *ca; + + if (!cpuacct_subsys.active) + return; + + ca = task_ca(tsk); + + for (; ca; ca = ca->parent) + percpu_counter_add(&ca->cpustat[idx], val); +} + struct cgroup_subsys cpuacct_subsys = { .name = "cpuacct", .create = cpuacct_create,
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