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Date: Fri, 2 Dec 2016 16:19:14 -0500
From: kan.liang@...el.com
To: peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
linux-kernel@...r.kernel.org
Cc: alexander.shishkin@...ux.intel.com, tglx@...utronix.de,
namhyung@...nel.org, jolsa@...nel.org, adrian.hunter@...el.com,
wangnan0@...wei.com, mark.rutland@....com, andi@...stfloor.org,
Kan Liang <kan.liang@...el.com>
Subject: [PATCH V2 06/13] perf tools: option to disable overhead collection
From: Kan Liang <kan.liang@...el.com>
Perf collects overhead information by default.
A new option --no-profile-cost-info is introduced to disable the
information collection.
Signed-off-by: Kan Liang <kan.liang@...el.com>
---
tools/include/uapi/linux/perf_event.h | 42 +++++++++++++++++++++++++++++++-
tools/perf/Documentation/perf-record.txt | 6 +++++
tools/perf/builtin-record.c | 2 ++
tools/perf/perf.h | 1 +
tools/perf/util/evsel.c | 1 +
5 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index c66a485..bdf2eec 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -344,7 +344,8 @@ struct perf_event_attr {
use_clockid : 1, /* use @clockid for time fields */
context_switch : 1, /* context switch data */
write_backward : 1, /* Write ring buffer from end to beginning */
- __reserved_1 : 36;
+ overhead : 1, /* Log overhead information */
+ __reserved_1 : 35;
union {
__u32 wakeup_events; /* wakeup every n events */
@@ -862,6 +863,17 @@ enum perf_event_type {
*/
PERF_RECORD_SWITCH_CPU_WIDE = 15,
+ /*
+ * Records perf overhead
+ * struct {
+ * struct perf_event_header header;
+ * u64 type;
+ * struct perf_overhead_entry entry;
+ * struct sample_id sample_id;
+ * };
+ */
+ PERF_RECORD_OVERHEAD = 16,
+
PERF_RECORD_MAX, /* non-ABI */
};
@@ -980,4 +992,32 @@ struct perf_branch_entry {
reserved:44;
};
+/*
+ * The overhead type could be different among architectures.
+ * The common overhead type can be defined from PERF_CORE_OVERHEAD
+ * The arch specific type should be defined from PERF_PMU_OVERHEAD
+ */
+enum perf_record_overhead_type {
+ PERF_CORE_OVERHEAD = 0,
+ PERF_CORE_MUX_OVERHEAD = 0,
+ PERF_CORE_SB_OVERHEAD,
+
+ PERF_PMU_OVERHEAD = 20,
+ PERF_PMU_SAMPLE_OVERHEAD = 20,
+
+ PERF_OVERHEAD_MAX,
+};
+
+/*
+ * single overhead record layout:
+ *
+ * nr: Times of overhead happens.
+ * E.g. for NMI, nr == times of NMI handler are called.
+ * time: Total overhead cost(ns)
+ */
+struct perf_overhead_entry {
+ __u64 nr;
+ __u64 time;
+};
+
#endif /* _UAPI_LINUX_PERF_EVENT_H */
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 27fc361..29a57f9 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -460,6 +460,12 @@ config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
Implies --tail-synthesize.
+--no-profile-cost-info::
+Perf collects profiling time cost by default.
+The time cost includes sampling overhead, multiplexing overhead, side-band
+events overhead and so on.
+This option disable the profiling time cost information collection.
+
SEE ALSO
--------
linkperf:perf-stat[1], linkperf:perf-list[1]
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 67d2a90..73b033b 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1512,6 +1512,8 @@ struct option __record_options[] = {
"Switch output when receive SIGUSR2"),
OPT_BOOLEAN(0, "dry-run", &dry_run,
"Parse options then exit"),
+ OPT_BOOLEAN(0, "no-profile-cost-info", &record.opts.no_profile_cost,
+ "Do not collect perf profiling time cost information"),
OPT_END()
};
diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 9a0236a..59b16d3 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -55,6 +55,7 @@ struct record_opts {
bool all_user;
bool tail_synthesize;
bool overwrite;
+ bool no_profile_cost;
unsigned int freq;
unsigned int mmap_pages;
unsigned int auxtrace_mmap_pages;
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index b2365a63..146c191 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -817,6 +817,7 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts,
attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1;
attr->inherit = !opts->no_inherit;
attr->write_backward = opts->overwrite ? 1 : 0;
+ attr->overhead = !opts->no_profile_cost;
perf_evsel__set_sample_bit(evsel, IP);
perf_evsel__set_sample_bit(evsel, TID);
--
2.5.5
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