The following commit has been merged into the sched/core branch of tip:
Commit-ID: 9525616d056e29f7900796cb0c19b38ad274b0eb
Gitweb: https://git.kernel.org/tip/9525616d056e29f7900796cb0c19b38ad274b0eb
Author: Huaixin Chang <changhuaixin@xxxxxxxxxxxxxxxxx>
AuthorDate: Mon, 30 Aug 2021 11:22:14 +08:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Thu, 09 Sep 2021 11:27:32 +02:00
sched/fair: Add cfs bandwidth burst statistics
Two new statistics are introduced to show the internal of burst feature
and explain why burst helps or not.
nr_bursts: number of periods bandwidth burst occurs
burst_time: cumulative wall-time (in nanoseconds) that any cpus has
used above quota in respective periods
Co-developed-by: Shanpei Chen <shanpeic@xxxxxxxxxxxxxxxxx>
Signed-off-by: Shanpei Chen <shanpeic@xxxxxxxxxxxxxxxxx>
Co-developed-by: Tianchen Ding <dtcccc@xxxxxxxxxxxxxxxxx>
Signed-off-by: Tianchen Ding <dtcccc@xxxxxxxxxxxxxxxxx>
Signed-off-by: Huaixin Chang <changhuaixin@xxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210830032215.16302-2-changhuaixin@xxxxxxxxxxxxxxxxx
---
kernel/sched/core.c | 13 ++++++++++---
kernel/sched/fair.c | 9 +++++++++
kernel/sched/sched.h | 3 +++
3 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 953ff36..2877138 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10244,6 +10244,9 @@ static int cpu_cfs_stat_show(struct seq_file *sf, void *v)
seq_printf(sf, "wait_sum %llu\n", ws);
}
+ seq_printf(sf, "nr_bursts %d\n", cfs_b->nr_burst);
+ seq_printf(sf, "burst_time %llu\n", cfs_b->burst_time);
+
return 0;
}
#endif /* CONFIG_CFS_BANDWIDTH */
@@ -10359,16 +10362,20 @@ static int cpu_extra_stat_show(struct seq_file *sf,
{
struct task_group *tg = css_tg(css);
struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
- u64 throttled_usec;
+ u64 throttled_usec, burst_usec;
throttled_usec = cfs_b->throttled_time;
do_div(throttled_usec, NSEC_PER_USEC);
+ burst_usec = cfs_b->burst_time;
+ do_div(burst_usec, NSEC_PER_USEC);
seq_printf(sf, "nr_periods %d\n"
"nr_throttled %d\n"
- "throttled_usec %llu\n",
+ "throttled_usec %llu\n"
+ "nr_bursts %d\n"
+ "burst_usec %llu\n",
cfs_b->nr_periods, cfs_b->nr_throttled,
- throttled_usec);
+ throttled_usec, cfs_b->nr_burst, burst_usec);
}
#endif
return 0;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b27ed8b..3594884 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4686,11 +4686,20 @@ static inline u64 sched_cfs_bandwidth_slice(void)
*/
void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
{
+ s64 runtime;
+
if (unlikely(cfs_b->quota == RUNTIME_INF))
return;
cfs_b->runtime += cfs_b->quota;
+ runtime = cfs_b->runtime_snap - cfs_b->runtime;
+ if (runtime > 0) {
+ cfs_b->burst_time += runtime;
+ cfs_b->nr_burst++;
+ }
+
cfs_b->runtime = min(cfs_b->runtime, cfs_b->quota + cfs_b->burst);
+ cfs_b->runtime_snap = cfs_b->runtime;
}
static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 6b2d8b7..094ea86 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -369,6 +369,7 @@ struct cfs_bandwidth {
u64 quota;
u64 runtime;
u64 burst;
+ u64 runtime_snap;
s64 hierarchical_quota;
u8 idle;
@@ -381,7 +382,9 @@ struct cfs_bandwidth {
/* Statistics: */
int nr_periods;
int nr_throttled;
+ int nr_burst;
u64 throttled_time;
+ u64 burst_time;
#endif
};
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