When recently using 'perf report --stat' it was not clear to me from the
output whether a particular statistics field (LOST_SAMPLES) was not
present, or just zero:
fomalhaut:~> perf report --stat
Aggregated stats:
TOTAL events: 495984
MMAP events: 85
COMM events: 3389
EXIT events: 1605
THROTTLE events: 2
UNTHROTTLE events: 2
FORK events: 3377
SAMPLE events: 472629
MMAP2 events: 14753
FINISHED_ROUND events: 139
THREAD_MAP events: 1
CPU_MAP events: 1
TIME_CONV events: 1
I had to check the output several times to ascertain that I'm not
misreading the output, that the field didn't change and that I didn't
misremember the name. In fact I had to look into the perf source to make
sure that zero fields are indeed not shown.
With the patch applied:
fomalhaut:~> perf report --stat
Aggregated stats:
TOTAL events: 495984
MMAP events: 85
LOST events: 0
COMM events: 3389
EXIT events: 1605
THROTTLE events: 2
UNTHROTTLE events: 2
FORK events: 3377
READ events: 0
SAMPLE events: 472629
MMAP2 events: 14753
AUX events: 0
ITRACE_START events: 0
LOST_SAMPLES events: 0
SWITCH events: 0
SWITCH_CPU_WIDE events: 0
NAMESPACES events: 0
ATTR events: 0
EVENT_TYPE events: 0
TRACING_DATA events: 0
BUILD_ID events: 0
FINISHED_ROUND events: 139
ID_INDEX events: 0
AUXTRACE_INFO events: 0
AUXTRACE events: 0
AUXTRACE_ERROR events: 0
THREAD_MAP events: 1
CPU_MAP events: 1
STAT_CONFIG events: 0
STAT events: 0
STAT_ROUND events: 0
EVENT_UPDATE events: 0
TIME_CONV events: 1
FEATURE events: 0
It's pretty clear at a glance that LOST_SAMPLES is present but zero.
The original output can still be gotten via:
fomalhaut:~> perf report --stat | grep -vw 0
Aggregated stats:
TOTAL events: 495984
MMAP events: 85
COMM events: 3389
EXIT events: 1605
THROTTLE events: 2
UNTHROTTLE events: 2
FORK events: 3377
SAMPLE events: 472629
MMAP2 events: 14753
FINISHED_ROUND events: 139
THREAD_MAP events: 1
CPU_MAP events: 1
TIME_CONV events: 1
So I don't think there's any real loss in functionality.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20180307152430.7e5h7e657b7bgd7q@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
39ce7fb315