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sched: include group statistics in /proc/sched_debug 

Impact: extend /proc/sched_debug info

Since the statistics of a group entity isn't exported directly from the
kernel, it becomes difficult to obtain some of the group statistics.
For example, the current method to obtain exec time of a group entity
is not always accurate. One has to read the exec times of all
the tasks(/proc/<pid>/sched) in the group and add them. This method
fails (or becomes difficult) if we want to collect stats of a group over
a duration where tasks get created and terminated.

This patch makes it easier to obtain group stats by directly including
them in /proc/sched_debug. Stats like group exec time would help user
programs (like LTP) to accurately measure the group fairness.

An example output of group stats from /proc/sched_debug:

cfs_rq[3]:/3/a/1
  .exec_clock                    : 89.598007
  .MIN_vruntime                  : 0.000001
  .min_vruntime                  : 256300.970506
  .max_vruntime                  : 0.000001
  .spread                        : 0.000000
  .spread0                       : -25373.372248
  .nr_running                    : 0
  .load                          : 0
  .yld_exp_empty                 : 0
  .yld_act_empty                 : 0
  .yld_both_empty                : 0
  .yld_count                     : 4474
  .sched_switch                  : 0
  .sched_count                   : 40507
  .sched_goidle                  : 12686
  .ttwu_count                    : 15114
  .ttwu_local                    : 11950
  .bkl_count                     : 67
  .nr_spread_over                : 0
  .shares                        : 0
  .se->exec_start                : 113676.727170
  .se->vruntime                  : 1592.612714
  .se->sum_exec_runtime          : 89.598007
  .se->wait_start                : 0.000000
  .se->sleep_start               : 0.000000
  .se->block_start               : 0.000000
  .se->sleep_max                 : 0.000000
  .se->block_max                 : 0.000000
  .se->exec_max                  : 1.000282
  .se->slice_max                 : 1.999750
  .se->wait_max                  : 54.981093
  .se->wait_sum                  : 217.610521
  .se->wait_count                : 50
  .se->load.weight               : 2

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Acked-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Bharata B Rao 2008-11-10 21:34:09 +05:30 committed by Ingo Molnar
parent ae1e9130bf
commit ff9b48c359
1 changed files with 36 additions and 1 deletions
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37
kernel/sched_debug.c
View File

@ -53,6 +53,40 @@ static unsigned long nsec_low(unsigned long long nsec)
#define SPLIT_NS(x) nsec_high(x), nsec_low(x)
#ifdef CONFIG_FAIR_GROUP_SCHED
static void print_cfs_group_stats(struct seq_file *m, int cpu,
struct task_group *tg)
{
struct sched_entity *se = tg->se[cpu];
if (!se)
return;
#define P(F) \
SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)F)
#define PN(F) \
SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
PN(se->exec_start);
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);
#endif
P(se->load.weight);
#undef PN
#undef P
}
#endif
static void
print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
{
@ -181,6 +215,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
#ifdef CONFIG_SMP
SEQ_printf(m, " .%-30s: %lu\n", "shares", cfs_rq->shares);
#endif
print_cfs_group_stats(m, cpu, cfs_rq->tg);
#endif
}
@ -261,7 +296,7 @@ static int sched_debug_show(struct seq_file *m, void *v)
u64 now = ktime_to_ns(ktime_get());
int cpu;
SEQ_printf(m, "Sched Debug Version: v0.07, %s %.*s\n",
SEQ_printf(m, "Sched Debug Version: v0.08, %s %.*s\n",
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);