diff options
| -rw-r--r-- | include/linux/perf_event.h | 4 | ||||
| -rw-r--r-- | kernel/perf_event.c | 43 | ||||
| -rw-r--r-- | kernel/sysctl.c | 2 |
3 files changed, 29 insertions, 20 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 38c8b255484..8ceb5a6fd9c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1110,6 +1110,10 @@ extern int sysctl_perf_event_paranoid; extern int sysctl_perf_event_mlock; extern int sysctl_perf_event_sample_rate; +extern int perf_proc_update_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos); + static inline bool perf_paranoid_tracepoint_raw(void) { return sysctl_perf_event_paranoid > -1; diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 65dcdc76d70..e03be08d0dd 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -150,7 +150,24 @@ int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */ /* * max perf event sample rate */ -int sysctl_perf_event_sample_rate __read_mostly = 100000; +#define DEFAULT_MAX_SAMPLE_RATE 100000 +int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; +static int max_samples_per_tick __read_mostly = + DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); + +int perf_proc_update_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret = proc_dointvec(table, write, buffer, lenp, ppos); + + if (ret || !write) + return ret; + + max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); + + return 0; +} static atomic64_t perf_event_id; @@ -4941,26 +4958,14 @@ static int __perf_event_overflow(struct perf_event *event, int nmi, if (unlikely(!is_sampling_event(event))) return 0; - if (!throttle) { - hwc->interrupts++; - } else { - if (hwc->interrupts != MAX_INTERRUPTS) { - hwc->interrupts++; - if (HZ * hwc->interrupts > - (u64)sysctl_perf_event_sample_rate) { - hwc->interrupts = MAX_INTERRUPTS; - perf_log_throttle(event, 0); - ret = 1; - } - } else { - /* - * Keep re-disabling events even though on the previous - * pass we disabled it - just in case we raced with a - * sched-in and the event got enabled again: - */ + if (unlikely(hwc->interrupts >= max_samples_per_tick)) { + if (throttle) { + hwc->interrupts = MAX_INTERRUPTS; + perf_log_throttle(event, 0); ret = 1; } - } + } else + hwc->interrupts++; if (event->attr.freq) { u64 now = perf_clock(); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 0f1bd83db98..daef911cbad 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -948,7 +948,7 @@ static struct ctl_table kern_table[] = { .data = &sysctl_perf_event_sample_rate, .maxlen = sizeof(sysctl_perf_event_sample_rate), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = perf_proc_update_handler, }, #endif #ifdef CONFIG_KMEMCHECK |