diff options
author | Josh Don <joshdon@google.com> | 2021-10-18 23:34:28 +0300 |
---|---|---|
committer | Peter Zijlstra <peterz@infradead.org> | 2021-11-17 16:49:00 +0300 |
commit | 4feee7d12603deca8775f9f9ae5e121093837444 (patch) | |
tree | 5b4d68bde6fbd540ec521237d75892b617241eac /kernel/sched/sched.h | |
parent | 2fb75e1b642f49253d8848c9e47e8942f5366221 (diff) | |
download | linux-4feee7d12603deca8775f9f9ae5e121093837444.tar.xz |
sched/core: Forced idle accounting
Adds accounting for "forced idle" time, which is time where a cookie'd
task forces its SMT sibling to idle, despite the presence of runnable
tasks.
Forced idle time is one means to measure the cost of enabling core
scheduling (ie. the capacity lost due to the need to force idle).
Forced idle time is attributed to the thread responsible for causing
the forced idle.
A few details:
- Forced idle time is displayed via /proc/PID/sched. It also requires
that schedstats is enabled.
- Forced idle is only accounted when a sibling hyperthread is held
idle despite the presence of runnable tasks. No time is charged if
a sibling is idle but has no runnable tasks.
- Tasks with 0 cookie are never charged forced idle.
- For SMT > 2, we scale the amount of forced idle charged based on the
number of forced idle siblings. Additionally, we split the time up and
evenly charge it to all running tasks, as each is equally responsible
for the forced idle.
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211018203428.2025792-1-joshdon@google.com
Diffstat (limited to 'kernel/sched/sched.h')
-rw-r--r-- | kernel/sched/sched.h | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 0e66749486e7..eb971151e7e4 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1111,8 +1111,10 @@ struct rq { unsigned int core_task_seq; unsigned int core_pick_seq; unsigned long core_cookie; - unsigned char core_forceidle; + unsigned int core_forceidle_count; unsigned int core_forceidle_seq; + unsigned int core_forceidle_occupation; + u64 core_forceidle_start; #endif }; @@ -1253,7 +1255,7 @@ static inline bool sched_core_enqueued(struct task_struct *p) } extern void sched_core_enqueue(struct rq *rq, struct task_struct *p); -extern void sched_core_dequeue(struct rq *rq, struct task_struct *p); +extern void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags); extern void sched_core_get(void); extern void sched_core_put(void); @@ -1854,6 +1856,32 @@ static inline void flush_smp_call_function_from_idle(void) { } #include "stats.h" #include "autogroup.h" +#if defined(CONFIG_SCHED_CORE) && defined(CONFIG_SCHEDSTATS) + +extern void __sched_core_account_forceidle(struct rq *rq); + +static inline void sched_core_account_forceidle(struct rq *rq) +{ + if (schedstat_enabled()) + __sched_core_account_forceidle(rq); +} + +extern void __sched_core_tick(struct rq *rq); + +static inline void sched_core_tick(struct rq *rq) +{ + if (sched_core_enabled(rq) && schedstat_enabled()) + __sched_core_tick(rq); +} + +#else + +static inline void sched_core_account_forceidle(struct rq *rq) {} + +static inline void sched_core_tick(struct rq *rq) {} + +#endif /* CONFIG_SCHED_CORE && CONFIG_SCHEDSTATS */ + #ifdef CONFIG_CGROUP_SCHED /* |