XXX write a tracer: - 'migirate_disable() -> migrate_enable()' time in task_sched_runtime() - 'migrate_pull -> sched-in' time in task_sched_runtime()
The first will give worst case for the second, which is the actual interference experienced by the task to due migration constraints of migrate_disable(). Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- include/trace/events/sched.h | 12 ++++++++++++ kernel/sched/core.c | 4 ++++ kernel/sched/deadline.c | 1 + kernel/sched/rt.c | 8 +++++++- 4 files changed, 24 insertions(+), 1 deletion(-) --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -646,6 +646,18 @@ DECLARE_TRACE(sched_update_nr_running_tp TP_PROTO(struct rq *rq, int change), TP_ARGS(rq, change)); +DECLARE_TRACE(sched_migrate_disable_tp, + TP_PROTO(struct task_struct *p), + TP_ARGS(p)); + +DECLARE_TRACE(sched_migrate_enable_tp, + TP_PROTO(struct task_struct *p), + TP_ARGS(p)); + +DECLARE_TRACE(sched_migrate_pull_tp, + TP_PROTO(struct task_struct *p), + TP_ARGS(p)); + #endif /* _TRACE_SCHED_H */ /* This part must be outside protection */ --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1732,6 +1732,8 @@ void migrate_disable(void) return; } + trace_sched_migrate_disable_tp(p); + preempt_disable(); this_rq()->nr_pinned++; p->migration_disabled = 1; @@ -1764,6 +1766,8 @@ void migrate_enable(void) p->migration_disabled = 0; this_rq()->nr_pinned--; preempt_enable(); + + trace_sched_migrate_enable_tp(p); } EXPORT_SYMBOL_GPL(migrate_enable); --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2245,6 +2245,7 @@ static void pull_dl_task(struct rq *this goto skip; if (is_migration_disabled(p)) { + trace_sched_migrate_pull_tp(p); push_task = get_push_task(src_rq); } else { deactivate_task(src_rq, p, 0); --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1877,7 +1877,12 @@ static int push_rt_task(struct rq *rq, b struct task_struct *push_task = NULL; int cpu; - if (!pull || rq->push_busy) + if (!pull) + return 0; + + trace_sched_migrate_pull_tp(next_task); + + if (rq->push_busy) return 0; cpu = find_lowest_rq(rq->curr); @@ -2223,6 +2228,7 @@ static void pull_rt_task(struct rq *this goto skip; if (is_migration_disabled(p)) { + trace_sched_migrate_pull_tp(p); push_task = get_push_task(src_rq); } else { deactivate_task(src_rq, p, 0);
