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Message-Id: <20210304164235.11384-1-changbin.du@gmail.com>
Date: Fri, 5 Mar 2021 00:42:35 +0800
From: Changbin Du <changbin.du@...il.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
linux-kernel@...r.kernel.org, Changbin Du <changbin.du@...il.com>
Subject: [PATCH v2] perf stat: improve readability of shadow stats
This adds function convert_unit_double() and selects appropriate
unit for shadow stats between K/M/G.
$ sudo ./perf stat -a -- sleep 1
Before: Unit 'M' is selected even the number is very small.
Performance counter stats for 'system wide':
4,003.06 msec cpu-clock # 3.998 CPUs utilized
16,179 context-switches # 0.004 M/sec
161 cpu-migrations # 0.040 K/sec
4,699 page-faults # 0.001 M/sec
6,135,801,925 cycles # 1.533 GHz (83.21%)
5,783,308,491 stalled-cycles-frontend # 94.26% frontend cycles idle (83.21%)
4,543,694,050 stalled-cycles-backend # 74.05% backend cycles idle (66.49%)
4,720,130,587 instructions # 0.77 insn per cycle
# 1.23 stalled cycles per insn (83.28%)
753,848,078 branches # 188.318 M/sec (83.61%)
37,457,747 branch-misses # 4.97% of all branches (83.48%)
1.001283725 seconds time elapsed
After:
$ sudo ./perf stat -a -- sleep 2
Performance counter stats for 'system wide':
8,005.52 msec cpu-clock # 3.999 CPUs utilized
10,715 context-switches # 1.338 K/sec
785 cpu-migrations # 98.057 /sec
102 page-faults # 12.741 /sec
1,948,202,279 cycles # 0.243 GHz
2,816,470,932 stalled-cycles-frontend # 144.57% frontend cycles idle
2,661,172,207 stalled-cycles-backend # 136.60% backend cycles idle
464,172,105 instructions # 0.24 insn per cycle
# 6.07 stalled cycles per insn
91,567,662 branches # 11.438 M/sec
7,756,054 branch-misses # 8.47% of all branches
2.002040043 seconds time elapsed
Signed-off-by: Changbin Du <changbin.du@...il.com>
v2:
o do not change 'sec' to 'cpu-sec'.
o use convert_unit_double to implement convert_unit.
---
tools/perf/util/stat-shadow.c | 16 +++++++---------
tools/perf/util/units.c | 21 ++++++++++++++-------
tools/perf/util/units.h | 1 +
3 files changed, 22 insertions(+), 16 deletions(-)
diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 6ccf21a72f06..3f800e71126f 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -9,6 +9,7 @@
#include "expr.h"
#include "metricgroup.h"
#include "cgroup.h"
+#include "units.h"
#include <linux/zalloc.h>
/*
@@ -1270,18 +1271,15 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
generic_metric(config, evsel->metric_expr, evsel->metric_events, NULL,
evsel->name, evsel->metric_name, NULL, 1, cpu, out, st);
} else if (runtime_stat_n(st, STAT_NSECS, cpu, &rsd) != 0) {
- char unit = 'M';
- char unit_buf[10];
+ char unit = ' ';
+ char unit_buf[10] = "/sec";
total = runtime_stat_avg(st, STAT_NSECS, cpu, &rsd);
-
if (total)
- ratio = 1000.0 * avg / total;
- if (ratio < 0.001) {
- ratio *= 1000;
- unit = 'K';
- }
- snprintf(unit_buf, sizeof(unit_buf), "%c/sec", unit);
+ ratio = convert_unit_double(1000000000.0 * avg / total, &unit);
+
+ if (unit != ' ')
+ snprintf(unit_buf, sizeof(unit_buf), "%c/sec", unit);
print_metric(config, ctxp, NULL, "%8.3f", unit_buf, ratio);
} else if (perf_stat_evsel__is(evsel, SMI_NUM)) {
print_smi_cost(config, cpu, out, st, &rsd);
diff --git a/tools/perf/util/units.c b/tools/perf/util/units.c
index a46762aec4c9..32c39cfe209b 100644
--- a/tools/perf/util/units.c
+++ b/tools/perf/util/units.c
@@ -33,28 +33,35 @@ unsigned long parse_tag_value(const char *str, struct parse_tag *tags)
return (unsigned long) -1;
}
-unsigned long convert_unit(unsigned long value, char *unit)
+double convert_unit_double(double value, char *unit)
{
*unit = ' ';
- if (value > 1000) {
- value /= 1000;
+ if (value > 1000.0) {
+ value /= 1000.0;
*unit = 'K';
}
- if (value > 1000) {
- value /= 1000;
+ if (value > 1000.0) {
+ value /= 1000.0;
*unit = 'M';
}
- if (value > 1000) {
- value /= 1000;
+ if (value > 1000.0) {
+ value /= 1000.0;
*unit = 'G';
}
return value;
}
+unsigned long convert_unit(unsigned long value, char *unit)
+{
+ double v = convert_unit_double((double)value, unit);
+
+ return (unsigned long)v;
+}
+
int unit_number__scnprintf(char *buf, size_t size, u64 n)
{
char unit[4] = "BKMG";
diff --git a/tools/perf/util/units.h b/tools/perf/util/units.h
index 99263b6a23f7..ea43e74e3240 100644
--- a/tools/perf/util/units.h
+++ b/tools/perf/util/units.h
@@ -12,6 +12,7 @@ struct parse_tag {
unsigned long parse_tag_value(const char *str, struct parse_tag *tags);
+double convert_unit_double(double value, char *unit);
unsigned long convert_unit(unsigned long value, char *unit);
int unit_number__scnprintf(char *buf, size_t size, u64 n);
--
2.25.1
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