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Groups > linux.kernel > #1369917
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: "perf: interrupt took too long" messages even with perf_cpu_time_max_percent==0 |
| Date | 2016-04-02 13:10 +0200 |
| Message-ID | <rjrBf-2Rm-1@gated-at.bofh.it> (permalink) |
| References | <rjqcb-1I3-39@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Sat, Apr 02, 2016 at 11:32:39AM +0200, Markus Trippelsdorf wrote:
> Current git kernel sometimes shows:
>
> perf: interrupt took too long (71 > 52), lowering kernel.perf_event_max_sample_rate to 300
> perf: interrupt took too long (103 > 88), lowering kernel.perf_event_max_sample_rate to 300
> perf: interrupt took too long (130 > 128), lowering kernel.perf_event_max_sample_rate to 300
> perf: interrupt took too long (175 > 162), lowering kernel.perf_event_max_sample_rate to 300
> perf: interrupt took too long (219 > 218), lowering kernel.perf_event_max_sample_rate to 300
> ...
>
> when running e.g. "perf top" even when
> /proc/sys/kernel/perf_cpu_time_max_percent is set to 0.
Ah, was 0 also meant to disable it?
Does the below help?
---
kernel/events/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8c3b35f2a269..21ba024c9ed1 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -412,7 +412,8 @@ int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
if (ret || !write)
return ret;
- if (sysctl_perf_cpu_time_max_percent == 100) {
+ if (sysctl_perf_cpu_time_max_percent == 100 ||
+ sysctl_perf_cpu_time_max_percent == 0) {
printk(KERN_WARNING
"perf: Dynamic interrupt throttling disabled, can hang your system!\n");
WRITE_ONCE(perf_sample_allowed_ns, 0);
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"perf: interrupt took too long" messages even with perf_cpu_time_max_percent==0 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-04-02 11:40 +0200
Re: "perf: interrupt took too long" messages even with perf_cpu_time_max_percent==0 Peter Zijlstra <peterz@infradead.org> - 2016-04-02 13:10 +0200
Re: "perf: interrupt took too long" messages even with perf_cpu_time_max_percent==0 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-04-02 13:20 +0200
Re: "perf: interrupt took too long" messages even with perf_cpu_time_max_percent==0 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-04-02 13:30 +0200
Re: "perf: interrupt took too long" messages even with perf_cpu_time_max_percent==0 Peter Zijlstra <peterz@infradead.org> - 2016-04-02 18:40 +0200
Re: "perf: interrupt took too long" messages even with perf_cpu_time_max_percent==0 Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-04-13 12:10 +0200
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