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>
1 file changed
