Remote wakeups of polling CPUs are a valuable performance improvement; add a tracepoint to make it much easier to verify that they're working.
Unified · Split
| @@ -530,6 +530,26 @@ TRACE_EVENT(sched_swap_numa, · 529 unmodified lines | ||
| 530 | 530 | __entry->dst_pid, __entry->dst_tgid, __entry->dst_ngid, |
| 531 | 531 | __entry->dst_cpu, __entry->dst_nid) |
| 532 | 532 | ); |
| 533 | + | |
| 534 | +/* | |
| 535 | + * Tracepoint for waking a polling cpu without an IPI. | |
| 536 | + */ | |
| 537 | +TRACE_EVENT(sched_wake_idle_without_ipi, | |
| 538 | + | |
| 539 | + TP_PROTO(int cpu), | |
| 540 | + | |
| 541 | + TP_ARGS(cpu), | |
| 542 | + | |
| 543 | + TP_STRUCT__entry( | |
| 544 | + __field( int, cpu ) | |
| 545 | + ), | |
| 546 | + | |
| 547 | + TP_fast_assign( | |
| 548 | + __entry->cpu = cpu; | |
| 549 | + ), | |
| 550 | + | |
| 551 | + TP_printk("cpu=%d", __entry->cpu) | |
| 552 | +); | |
| 533 | 553 | #endif /* _TRACE_SCHED_H */ |
| 534 | 554 | |
| 535 | 555 | /* This part must be outside protection */ |
| @@ -564,6 +564,8 @@ void resched_task(struct task_struct *p) · 563 unmodified lines | ||
| 564 | 564 | |
| 565 | 565 | if (set_nr_and_not_polling(p)) |
| 566 | 566 | smp_send_reschedule(cpu); |
| 567 | + else | |
| 568 | + trace_sched_wake_idle_without_ipi(cpu); | |
| 567 | 569 | } |
| 568 | 570 | |
| 569 | 571 | void resched_cpu(int cpu) |
| @@ -647,6 +649,8 @@ static void wake_up_idle_cpu(int cpu) · 77 unmodified lines | ||
| 647 | 649 | smp_mb(); |
| 648 | 650 | if (!tsk_is_polling(rq->idle)) |
| 649 | 651 | smp_send_reschedule(cpu); |
| 652 | + else | |
| 653 | + trace_sched_wake_idle_without_ipi(cpu); | |
| 650 | 654 | } |
| 651 | 655 | |
| 652 | 656 | static bool wake_up_full_nohz_cpu(int cpu) |