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 | __entry->dst_pid, __entry->dst_tgid, __entry->dst_ngid, | 530 | __entry->dst_pid, __entry->dst_tgid, __entry->dst_ngid, |
| 531 | __entry->dst_cpu, __entry->dst_nid) | 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 | #endif /* _TRACE_SCHED_H */ | 553 | #endif /* _TRACE_SCHED_H */ |
| 534 | 554 | ||
| 535 | /* This part must be outside protection */ | 555 | /* This part must be outside protection */ |
| @@ -564,6 +564,8 @@ void resched_task(struct task_struct *p) · 563 unmodified lines | |||
| 564 | 564 | ||
| 565 | if (set_nr_and_not_polling(p)) | 565 | if (set_nr_and_not_polling(p)) |
| 566 | smp_send_reschedule(cpu); | 566 | smp_send_reschedule(cpu); |
| 567 | else | ||
| 568 | trace_sched_wake_idle_without_ipi(cpu); | ||
| 567 | } | 569 | } |
| 568 | 570 | ||
| 569 | void resched_cpu(int cpu) | 571 | void resched_cpu(int cpu) |
| @@ -647,6 +649,8 @@ static void wake_up_idle_cpu(int cpu) · 77 unmodified lines | |||
| 647 | smp_mb(); | 649 | smp_mb(); |
| 648 | if (!tsk_is_polling(rq->idle)) | 650 | if (!tsk_is_polling(rq->idle)) |
| 649 | smp_send_reschedule(cpu); | 651 | smp_send_reschedule(cpu); |
| 652 | else | ||
| 653 | trace_sched_wake_idle_without_ipi(cpu); | ||
| 650 | } | 654 | } |
| 651 | 655 | ||
| 652 | static bool wake_up_full_nohz_cpu(int cpu) | 656 | static bool wake_up_full_nohz_cpu(int cpu) |