perf stat: Add -o and --append options
This patch adds an option (-o) to save the output of perf stat into a
file. You could do this with perf record but not with perf stat.
Instead, you had to fiddle with stderr to save the counts into a
separate file.
The patch also adds the --append option so that results can be
concatenated into a single file across runs. Each run of the tool is
clearly separated by a comment line starting with a hash mark. The -A
option of perf record is already used by perf stat, so we only add a
long option.
$ perf stat -o res.txt date
$ cat res.txt
Performance counter stats for 'date':
0.791306 task-clock # 0.668 CPUs utilized
2 context-switches # 0.003 M/sec
0 CPU-migrations # 0.000 M/sec
197 page-faults # 0.249 M/sec
1878143 cycles # 2.373 GHz
<not supported> stalled-cycles-frontend
<not supported> stalled-cycles-backend
1083367 instructions # 0.58 insns per cycle
193027 branches # 243.935 M/sec
9014 branch-misses # 4.67% of all branches
0.001184746 seconds time elapsed
The option can be combined with -x to make the output file much easier
to parse.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20110815202233.GA18535@quad
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
3 files changed