On Tue, Mar 04, 2014 at 02:24:37AM +0100, Jean Pihet wrote:
Hi,
Here are some notes about the performance improvement and the test usage.
Jiri, do you need these notes in the one of commit description?
- Using libdw vs libunwind on ARMv7
The performance gain is (more than) significant: >800%.
I did not profile perf itself ;-p just did a timing measurement. The benchmark has been run multiple times with different perf.data sizes. The results are consistent across the tests runs.
Usage: ./tools/perf/perf record --call-graph dwarf -- ../../libunwind/test_app/stress_bt time ./tools/perf/perf report --stdio > /dev/null 2>&1
Platform: Quad-core marvell XP370. perf runs on 1 cpu
Perf data size: 304MB libunwind libdw improvement real 9m31.577s 1m13.052s 782% user 5m33.020s 1m2.910s 529% sys 3m57.770s 0m10.090s 2356%
- unwind test usage
perf test list gives the list of supported tests. In this case the test #23 is dwarf unwinding:
./tools/perf/perf test 23 23: Test dwarf unwind : Ok
Regards, Jean
I can't speak for the arm specific stuff, but generally it fits and looks ok (and does not break the x86 build)
also.. who wouldn't ack 800% speed improvement ;-)
Acked-by: Jiri Olsa jolsa@redhat.com
thanks, jirka