From 847fc0cd0664fcb2a08ac66df6b85935361ec454 Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Sun, 5 Sep 2021 14:35:43 +0000 Subject: [PATCH] sched: Introduce task block time in schedstats Currently in schedstats we have sum_sleep_runtime and iowait_sum, but there's no metric to show how long the task is in D state. Once a task in D state, it means the task is blocked in the kernel, for example the task may be waiting for a mutex. The D state is more frequent than iowait, and it is more critital than S state. So it is worth to add a metric to measure it. Signed-off-by: Yafang Shao Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210905143547.4668-5-laoar.shao@gmail.com --- include/linux/sched.h | 2 ++ kernel/sched/debug.c | 6 ++++-- kernel/sched/stats.c | 1 + 3 files changed, 7 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 2bc4c72fec2d..193e16e2d0e4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -503,6 +503,8 @@ struct sched_statistics { u64 block_start; u64 block_max; + s64 sum_block_runtime; + u64 exec_max; u64 slice_max; diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 76fd38ea844c..26fac5e28bc0 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -540,10 +540,11 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) (long long)(p->nvcsw + p->nivcsw), p->prio); - SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld", + SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld %9lld.%06ld", SPLIT_NS(schedstat_val_or_zero(p->stats.wait_sum)), SPLIT_NS(p->se.sum_exec_runtime), - SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime))); + SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime)), + SPLIT_NS(schedstat_val_or_zero(p->stats.sum_block_runtime))); #ifdef CONFIG_NUMA_BALANCING SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p)); @@ -977,6 +978,7 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, u64 avg_atom, avg_per_cpu; PN_SCHEDSTAT(sum_sleep_runtime); + PN_SCHEDSTAT(sum_block_runtime); PN_SCHEDSTAT(wait_start); PN_SCHEDSTAT(sleep_start); PN_SCHEDSTAT(block_start); diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c index fad781ca7791..07dde2928c79 100644 --- a/kernel/sched/stats.c +++ b/kernel/sched/stats.c @@ -82,6 +82,7 @@ void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p, __schedstat_set(stats->block_start, 0); __schedstat_add(stats->sum_sleep_runtime, delta); + __schedstat_add(stats->sum_block_runtime, delta); if (p) { if (p->in_iowait) { -- 2.11.0