Messages in this thread Patch in this message | | | From | Huaixin Chang <> | Subject | [PATCH v6 2/3] sched/fair: Add cfs bandwidth burst statistics | Date | Mon, 21 Jun 2021 17:27:59 +0800 |
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The following statistics in cpu.stat file is added to show how much workload is making use of cfs_b burst:
nr_bursts: number of periods bandwidth burst occurs burst_usec: cumulative wall-time that any cpus has used above quota in respective periods
The larger nr_bursts is, the more bursty periods there are. And the larger burst_usec is, the more burst time is used by bursty workload.
Co-developed-by: Shanpei Chen <shanpeic@linux.alibaba.com> Signed-off-by: Shanpei Chen <shanpeic@linux.alibaba.com> Co-developed-by: Tianchen Ding <dtcccc@linux.alibaba.com> Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com> Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com> --- kernel/sched/core.c | 13 ++++++++++--- kernel/sched/fair.c | 11 +++++++++++ kernel/sched/sched.h | 3 +++ 3 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b58ced2194a0..1e41c51b14b5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9265,6 +9265,9 @@ 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_usec %llu\n", cfs_b->burst_time); + return 0; } #endif /* CONFIG_CFS_BANDWIDTH */ @@ -9361,16 +9364,20 @@ 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 53d7cc4d009b..62b73722e510 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4634,11 +4634,22 @@ static inline u64 sched_cfs_bandwidth_slice(void) */ void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b) { + u64 runtime; + if (unlikely(cfs_b->quota == RUNTIME_INF)) return; + if (cfs_b->runtime_at_period_start > cfs_b->runtime) { + runtime = cfs_b->runtime_at_period_start - cfs_b->runtime; + if (runtime > cfs_b->quota) { + cfs_b->burst_time += runtime - cfs_b->quota; + cfs_b->nr_burst++; + } + } + cfs_b->runtime += cfs_b->quota; cfs_b->runtime = min(cfs_b->runtime, cfs_b->quota + cfs_b->burst); + cfs_b->runtime_at_period_start = 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 d317ca74a48c..b770b553dfbb 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -367,6 +367,7 @@ struct cfs_bandwidth { u64 quota; u64 runtime; u64 burst; + u64 runtime_at_period_start; s64 hierarchical_quota; u8 idle; @@ -379,7 +380,9 @@ struct cfs_bandwidth { /* Statistics: */ int nr_periods; int nr_throttled; + int nr_burst; u64 throttled_time; + u64 burst_time; #endif }; -- 2.14.4.44.g2045bb6
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