From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: lkml <linux-kernel@vger.kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-perf-users@vger.kernel.org,
Arnaldo Carvalho de Melo <acme@kernel.org>,
eranian@google.com, vincent.weaver@maine.edu,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Subject: Re: System crash with perf_fuzzer (kernel: 5.0.0-rc3)
Date: Thu, 31 Jan 2019 13:28:34 +0530 [thread overview]
Message-ID: <33d300b5-f8b0-4987-4d4c-b5175b6b6c60@linux.ibm.com> (raw)
In-Reply-To: <20190125160056.GG6118@tassilo.jf.intel.com>
Hi Andi,
On 1/25/19 9:30 PM, Andi Kleen wrote:
>> [Fri Jan 25 10:28:53 2019] perf: interrupt took too long (2501 > 2500), lowering kernel.perf_event_max_sample_rate to 79750
>> [Fri Jan 25 10:29:08 2019] perf: interrupt took too long (3136 > 3126), lowering kernel.perf_event_max_sample_rate to 63750
>> [Fri Jan 25 10:29:11 2019] perf: interrupt took too long (4140 > 3920), lowering kernel.perf_event_max_sample_rate to 48250
>> [Fri Jan 25 10:29:11 2019] perf: interrupt took too long (5231 > 5175), lowering kernel.perf_event_max_sample_rate to 38000
>> [Fri Jan 25 10:29:11 2019] perf: interrupt took too long (6736 > 6538), lowering kernel.perf_event_max_sample_rate to 29500
>
> These are fairly normal.
I understand that throttling mechanism is designed exactly to do this.
But I've observed that, everytime I run the fuzzer, max_sample_rates is
been throttled down to 250 (which is CONFIG_HZ I guess). Doesn't this
mean the interrupt time is somehow increasing gradually? Is that fine?
Here is the sample dmesg:
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (2928 > 2500), lowering kernel.perf_event_max_sample_rate to 68250
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (4363 > 3660), lowering kernel.perf_event_max_sample_rate to 45750
[Thu Jan 31 09:25:40 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 2.183 msecs
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (21382 > 5453), lowering kernel.perf_event_max_sample_rate to 9250
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (34548 > 26727), lowering kernel.perf_event_max_sample_rate to 5750
[Thu Jan 31 09:25:40 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 3.509 msecs
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (61682 > 43185), lowering kernel.perf_event_max_sample_rate to 3000
[Thu Jan 31 09:25:40 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 3.593 msecs
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (89206 > 77102), lowering kernel.perf_event_max_sample_rate to 2000
[Thu Jan 31 09:25:40 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 3.619 msecs
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (120188 > 111507), lowering kernel.perf_event_max_sample_rate to 1500
[Thu Jan 31 09:25:40 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 3.782 msecs
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (171065 > 150235), lowering kernel.perf_event_max_sample_rate to 1000
[Thu Jan 31 09:25:40 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 4.066 msecs
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (226815 > 213831), lowering kernel.perf_event_max_sample_rate to 750
[Thu Jan 31 09:25:40 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 5.364 msecs
[Thu Jan 31 09:25:40 2019] perf: interrupt took too long (300844 > 283518), lowering kernel.perf_event_max_sample_rate to 500
[Thu Jan 31 09:33:43 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 6.136 msecs
[Thu Jan 31 09:50:35 2019] perf: interrupt took too long (378352 > 376055), lowering kernel.perf_event_max_sample_rate to 500
[Thu Jan 31 09:53:47 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 6.456 msecs
[Thu Jan 31 09:57:31 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 11.002 msecs
[Thu Jan 31 10:01:30 2019] perf: interrupt took too long (478447 > 472940), lowering kernel.perf_event_max_sample_rate to 250
[Thu Jan 31 12:28:31 2019] perf: interrupt took too long (601630 > 598058), lowering kernel.perf_event_max_sample_rate to 250
[Thu Jan 31 12:28:31 2019] perf: interrupt took too long (754288 > 752037), lowering kernel.perf_event_max_sample_rate to 250
[Thu Jan 31 12:43:13 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 12.781 msecs
[Thu Jan 31 12:43:13 2019] INFO: NMI handler (perf_event_nmi_handler) took too long to run: 13.583 msecs
Thanks,
Ravi
next prev parent reply other threads:[~2019-01-31 7:58 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 6:46 System crash with perf_fuzzer (kernel: 5.0.0-rc3) Ravi Bangoria
2019-01-25 15:11 ` Vince Weaver
2019-01-25 16:00 ` Andi Kleen
2019-01-31 7:58 ` Ravi Bangoria [this message]
2019-01-31 13:00 ` Andi Kleen
2019-01-31 20:27 ` Cong Wang
2019-01-31 20:39 ` Andi Kleen
2019-03-06 23:09 ` Pavel Machek
2019-01-30 18:36 ` Jiri Olsa
2019-01-30 20:39 ` Andi Kleen
2019-01-30 22:33 ` Jiri Olsa
2019-01-31 7:36 ` Jiri Olsa
2019-01-31 8:27 ` Jiri Olsa
2019-02-01 7:43 ` Jiri Olsa
2019-02-01 7:54 ` Ravi Bangoria
2019-02-02 3:24 ` Ravi Bangoria
2019-02-02 10:34 ` Jiri Olsa
2019-02-01 16:27 ` Vince Weaver
2019-02-01 17:38 ` Jiri Olsa
2019-02-02 17:58 ` Vince Weaver
2019-02-04 12:35 ` [PATCH] perf: Add check_period pmu callback Jiri Olsa
2019-02-11 10:11 ` Peter Zijlstra
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