The ratio between the number of events and the time elapsed makes
sense only if task-clock event is counted. Otherwise it will be
simply a (confusing)
# 0.000 M/sec
This patch outputs the ratio only if task-clock event is counted.
Some test examples of before and after:
Before:
[lucas@skywalker linux.trees.git]$ sudo perf stat -e branch-misses -a -- sleep 1
Performance counter stats for 'sleep 1':
1367818 branch-misses # 0.000 M/sec
1.001494325 seconds time elapsed
After (without task-clock):
[lucas@skywalker perf]$ sudo ./perf stat -e branch-misses -a -- sleep 1
Performance counter stats for 'sleep 1':
1135044 branch-misses
1.001370775 seconds time elapsed
After (with task-clock):
[lucas@skywalker perf]$ sudo ./perf stat -e branch-misses -e task-clock -a -- sleep 1
Performance counter stats for 'sleep 1':
1070111 branch-misses # 0.534 M/sec
2002.730893 task-clock-msecs # 1.999 CPUs
1.001640292 seconds time elapsed
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20091115140507.GB21561@skywalker.lan>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
7255fe2a42