perf report: Add --cumulate option

When --cumulate option is given, it will print accumulated hist stat
information.  It requires callchain information.

Cc: Arun Sharma <asharma@fb.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
1 file changed