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Groups > linux.kernel > #1528652
| From | kan.liang@intel.com |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 13/14] perf tools: warn on high overhead |
| Date | 2016-11-23 18:50 +0100 |
| Message-ID | <sGJQe-7SF-41@gated-at.bofh.it> (permalink) |
| References | <sGJQd-7SF-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Kan Liang <kan.liang@intel.com>
The rough overhead rate can be caculated by the sum of all kinds of
overhead / elapsed time.
If the overhead rate is higher than 10%, warning the user.
Signed-off-by: Kan Liang <kan.liang@intel.com>
---
tools/perf/util/session.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index e84808f..decfc48 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1559,6 +1559,30 @@ perf_session__warn_order(const struct perf_session *session)
ui__warning("%u out of order events recorded.\n", oe->nr_unordered_events);
}
+static void
+perf_session__warn_overhead(const struct perf_session *session)
+{
+ const struct events_stats *stats = &session->evlist->stats;
+ double overhead_rate;
+ u64 overhead;
+ int i;
+
+ for (i = 0; i < session->header.env.nr_cpus_online; i++) {
+ overhead = stats->total_nmi_overhead[i][1];
+ overhead += stats->total_mux_overhead[i][1];
+ overhead += stats->total_sb_overhead[i][1];
+ overhead += stats->total_user_write_overhead[i][1];
+
+ overhead_rate = (double)overhead / (double)stats->elapsed_time;
+
+ if (overhead_rate > 0.1) {
+ ui__warning("Perf overhead is high! The overhead rate is %3.2f%% on CPU %d\n\n"
+ "Please consider reducing the number of events, or increasing the period, or decrease the frequency.\n\n",
+ overhead_rate * 100.0, i);
+ }
+ }
+}
+
static void perf_session__warn_about_errors(const struct perf_session *session)
{
const struct events_stats *stats = &session->evlist->stats;
@@ -1632,6 +1656,8 @@ static void perf_session__warn_about_errors(const struct perf_session *session)
"Increase it by --proc-map-timeout\n",
stats->nr_proc_map_timeout);
}
+
+ perf_session__warn_overhead(session);
}
static int perf_session__flush_thread_stack(struct thread *thread,
--
2.5.5
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[PATCH 00/14] export perf overheads information kan.liang@intel.com - 2016-11-23 18:50 +0100
[PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Peter Zijlstra <peterz@infradead.org> - 2016-11-23 21:20 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Peter Zijlstra <peterz@infradead.org> - 2016-11-23 21:20 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:50 +0100
RE: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD "Liang, Kan" <kan.liang@intel.com> - 2016-11-24 14:50 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Peter Zijlstra <peterz@infradead.org> - 2016-11-24 15:00 +0100
RE: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD "Liang, Kan" <kan.liang@intel.com> - 2016-11-24 15:10 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Jiri Olsa <jolsa@redhat.com> - 2016-11-24 15:30 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Jiri Olsa <jolsa@redhat.com> - 2016-11-24 15:50 +0100
RE: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD "Liang, Kan" <kan.liang@intel.com> - 2016-11-24 15:50 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Andi Kleen <andi@firstfloor.org> - 2016-11-24 19:30 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Peter Zijlstra <peterz@infradead.org> - 2016-11-24 20:00 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Andi Kleen <andi@firstfloor.org> - 2016-11-24 20:10 +0100
Re: [PATCH 01/14] perf/x86: Introduce PERF_RECORD_OVERHEAD Peter Zijlstra <peterz@infradead.org> - 2016-11-24 20:10 +0100
[PATCH 11/14] perf tools: record write data overhead kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 11/14] perf tools: record write data overhead Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:10 +0100
Re: [PATCH 11/14] perf tools: record write data overhead Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:20 +0100
[PATCH 04/14] perf/x86: output side-band events overhead kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 04/14] perf/x86: output side-band events overhead Peter Zijlstra <peterz@infradead.org> - 2016-11-23 21:10 +0100
Re: [PATCH 04/14] perf/x86: output side-band events overhead Mark Rutland <mark.rutland@arm.com> - 2016-11-24 17:30 +0100
RE: [PATCH 04/14] perf/x86: output side-band events overhead "Liang, Kan" <kan.liang@intel.com> - 2016-11-24 20:50 +0100
[PATCH 07/14] perf tools: show multiplexing overhead kan.liang@intel.com - 2016-11-23 18:50 +0100
[PATCH 08/14] perf tools: show side-band events overhead kan.liang@intel.com - 2016-11-23 18:50 +0100
[PATCH 05/14] perf tools: handle PERF_RECORD_OVERHEAD record type kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 05/14] perf tools: handle PERF_RECORD_OVERHEAD record type Jiri Olsa <jolsa@redhat.com> - 2016-11-23 23:40 +0100
Re: [PATCH 05/14] perf tools: handle PERF_RECORD_OVERHEAD record type Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:00 +0100
[PATCH 12/14] perf tools: record elapsed time kan.liang@intel.com - 2016-11-23 18:50 +0100
[PATCH 13/14] perf tools: warn on high overhead kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 13/14] perf tools: warn on high overhead Andi Kleen <andi@firstfloor.org> - 2016-11-23 21:30 +0100
RE: [PATCH 13/14] perf tools: warn on high overhead "Liang, Kan" <kan.liang@intel.com> - 2016-11-23 23:10 +0100
[PATCH 14/14] perf script: show overhead events kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 14/14] perf script: show overhead events Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:30 +0100
Re: [PATCH 14/14] perf script: show overhead events Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:30 +0100
Re: [PATCH 14/14] perf script: show overhead events Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:40 +0100
Re: [PATCH 14/14] perf script: show overhead events Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:40 +0100
[PATCH 03/14] perf/x86: output multiplexing overhead kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 03/14] perf/x86: output multiplexing overhead Peter Zijlstra <peterz@infradead.org> - 2016-11-23 21:10 +0100
RE: [PATCH 03/14] perf/x86: output multiplexing overhead "Liang, Kan" <kan.liang@intel.com> - 2016-11-23 21:20 +0100
[PATCH 10/14] perf tools: introduce PERF_RECORD_USER_OVERHEAD kan.liang@intel.com - 2016-11-23 18:50 +0100
[PATCH 06/14] perf tools: show NMI overhead kan.liang@intel.com - 2016-11-23 18:50 +0100
Re: [PATCH 06/14] perf tools: show NMI overhead Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:00 +0100
Re: [PATCH 06/14] perf tools: show NMI overhead Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:00 +0100
RE: [PATCH 06/14] perf tools: show NMI overhead "Liang, Kan" <kan.liang@intel.com> - 2016-11-24 14:40 +0100
Re: [PATCH 06/14] perf tools: show NMI overhead Jiri Olsa <jolsa@redhat.com> - 2016-11-24 16:30 +0100
Re: [PATCH 06/14] perf tools: show NMI overhead Namhyung Kim <namhyung@kernel.org> - 2016-11-25 00:30 +0100
Re: [PATCH 06/14] perf tools: show NMI overhead Jiri Olsa <jolsa@redhat.com> - 2016-11-25 00:50 +0100
Re: [PATCH 06/14] perf tools: show NMI overhead Andi Kleen <andi@firstfloor.org> - 2016-11-25 01:30 +0100
Re: [PATCH 06/14] perf tools: show NMI overhead Jiri Olsa <jolsa@redhat.com> - 2016-11-24 00:00 +0100
Re: [PATCH 00/14] export perf overheads information Ingo Molnar <mingo@kernel.org> - 2016-11-24 05:30 +0100
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