[tip:perf/stat] perf stat: Print cache misses as percentage

From: tip-bot for Ingo Molnar
Date: Wed Apr 27 2011 - 12:00:16 EST


Commit-ID: d58f4c82fed69fdd4a79fa54fe17fd14d98c27aa
Gitweb: http://git.kernel.org/tip/d58f4c82fed69fdd4a79fa54fe17fd14d98c27aa
Author: Ingo Molnar <mingo@xxxxxxx>
AuthorDate: Wed, 27 Apr 2011 03:42:18 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Tue, 26 Apr 2011 20:04:54 +0200

perf stat: Print cache misses as percentage

Before:

113,393,041 cache-references # 83.636 M/sec
7,052,454 cache-misses # 5.202 M/sec

After:

112,589,441 cache-references # 87.925 M/sec
6,556,354 cache-misses # 5.823 %

misses/hits percentages are more expressive than absolute numbers
or rates.

(Also prettify the CPUs printout line to not have a trailing whitespace.)

Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Acked-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-axm28f43x439bl41zkvfzd63@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
tools/perf/builtin-stat.c | 18 +++++++++++++++---
1 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 3a29041..0de3a20 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -157,6 +157,7 @@ static double stddev_stats(struct stats *stats)
struct stats runtime_nsecs_stats[MAX_NR_CPUS];
struct stats runtime_cycles_stats[MAX_NR_CPUS];
struct stats runtime_branches_stats[MAX_NR_CPUS];
+struct stats runtime_cacherefs_stats[MAX_NR_CPUS];
struct stats walltime_nsecs_stats;

static int create_perf_stat_counter(struct perf_evsel *evsel)
@@ -219,10 +220,12 @@ static int read_counter_aggr(struct perf_evsel *counter)
*/
if (perf_evsel__match(counter, SOFTWARE, SW_TASK_CLOCK))
update_stats(&runtime_nsecs_stats[0], count[0]);
- if (perf_evsel__match(counter, HARDWARE, HW_CPU_CYCLES))
+ else if (perf_evsel__match(counter, HARDWARE, HW_CPU_CYCLES))
update_stats(&runtime_cycles_stats[0], count[0]);
- if (perf_evsel__match(counter, HARDWARE, HW_BRANCH_INSTRUCTIONS))
+ else if (perf_evsel__match(counter, HARDWARE, HW_BRANCH_INSTRUCTIONS))
update_stats(&runtime_branches_stats[0], count[0]);
+ else if (perf_evsel__match(counter, HARDWARE, HW_CACHE_REFERENCES))
+ update_stats(&runtime_cacherefs_stats[0], count[0]);

return 0;
}
@@ -404,7 +407,7 @@ static void nsec_printout(int cpu, struct perf_evsel *evsel, double avg)
return;

if (perf_evsel__match(evsel, SOFTWARE, SW_TASK_CLOCK))
- fprintf(stderr, " # %10.3f CPUs ",
+ fprintf(stderr, " # %10.3f CPUs",
avg / avg_stats(&walltime_nsecs_stats));
}

@@ -452,6 +455,15 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)

fprintf(stderr, " # %10.3f %%", ratio);

+ } else if (perf_evsel__match(evsel, HARDWARE, HW_CACHE_MISSES) &&
+ runtime_cacherefs_stats[cpu].n != 0) {
+ total = avg_stats(&runtime_cacherefs_stats[cpu]);
+
+ if (total)
+ ratio = avg * 100 / total;
+
+ fprintf(stderr, " # %10.3f %%", ratio);
+
} else if (runtime_nsecs_stats[cpu].n != 0) {
total = avg_stats(&runtime_nsecs_stats[cpu]);

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