Messages in this thread | | | Subject | Re: [PATCH] perf stat: improve readability of shadow stats | From | kajoljain <> | Date | Tue, 2 Mar 2021 12:23:25 +0530 |
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On 3/1/21 10:54 PM, Changbin Du wrote: > This does follow two changes: > 1) Select appropriate unit between K/M/G. > 2) Use 'cpu-sec' instead of 'sec' to state this is not the wall-time. > > $ 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': > > 8,003.20 msec cpu-clock # 3.998 CPUs utilized > 9,768 context-switches # 1.221 K/cpu-sec > 164 cpu-migrations # 20.492 /cpu-sec > 74,146 page-faults # 9.265 K/cpu-sec > 19,008,796,806 cycles # 2.375 GHz (83.21%) > 14,789,443,853 stalled-cycles-frontend # 77.80% frontend cycles idle (83.29%) > 11,867,812,064 stalled-cycles-backend # 62.43% backend cycles idle (66.80%) > 9,898,252,603 instructions # 0.52 insn per cycle > # 1.49 stalled cycles per insn (83.41%) > 2,063,251,998 branches # 257.803 M/cpu-sec (83.41%) > 86,941,704 branch-misses # 4.21% of all branches (83.30%) > > 2.001743706 seconds time elapsed > > Signed-off-by: Changbin Du <changbin.du@gmail.com> > --- > tools/perf/util/stat-shadow.c | 13 +++++-------- > tools/perf/util/units.c | 22 ++++++++++++++++++++++ > tools/perf/util/units.h | 1 + > 3 files changed, 28 insertions(+), 8 deletions(-) > > diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c > index 6ccf21a72f06..786b5ef512d8 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 +1271,14 @@ 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 = ' '; > char unit_buf[10]; > > 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); > + > + snprintf(unit_buf, sizeof(unit_buf), "%c/cpu-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..ac13b5ecde31 100644 > --- a/tools/perf/util/units.c > +++ b/tools/perf/util/units.c > @@ -55,6 +55,28 @@ unsigned long convert_unit(unsigned long value, char *unit) > return value; > } >
Hi Changbin, Since we are using added function `convert_unit_double` just in stat-shadow.c, I think there is no need to add it in units.h, we can directly create static func inside `stat-shadow.c`itself.
Thanks, Kajol Jain
> +double convert_unit_double(double value, char *unit) > +{ > + *unit = ' '; > + > + if (value > 1000.0) { > + value /= 1000.0; > + *unit = 'K'; > + } > + > + if (value > 1000.0) { > + value /= 1000.0; > + *unit = 'M'; > + } > + > + if (value > 1000.0) { > + value /= 1000.0; > + *unit = 'G'; > + } > + > + return value; > +} > + > 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..b3ace67ac16f 100644 > --- a/tools/perf/util/units.h > +++ b/tools/perf/util/units.h > @@ -13,6 +13,7 @@ struct parse_tag { > unsigned long parse_tag_value(const char *str, struct parse_tag *tags); > > unsigned long convert_unit(unsigned long value, char *unit); > +double convert_unit_double(double value, char *unit); > int unit_number__scnprintf(char *buf, size_t size, u64 n); > > #endif /* PERF_UNIT_H */ >
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