From bcb1704a1ed2de580a46f28922e223a65f16e0f5 Mon Sep 17 00:00:00 2001 From: Huaixin Chang Date: Mon, 30 Aug 2021 11:22:14 +0800 Subject: 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 Signed-off-by: Shanpei Chen Co-developed-by: Tianchen Ding Signed-off-by: Tianchen Ding Signed-off-by: Huaixin Chang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Daniel Jordan Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20210830032215.16302-2-changhuaixin@linux.alibaba.com --- kernel/sched/core.c | 13 ++++++++++--- kernel/sched/fair.c | 9 +++++++++ kernel/sched/sched.h | 3 +++ 3 files changed, 22 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f963c8113375..ccb604a1bd22 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -10406,6 +10406,9 @@ 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 */ @@ -10521,16 +10524,20 @@ 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 5457c8001c2a..fd41abef1950 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4715,11 +4715,20 @@ 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 15a8895698b9..8712fc431417 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 }; -- cgit