aboutsummaryrefslogtreecommitdiffstats
path: root/tools
diff options
context:
space:
mode:
authorMilian Wolff <milian.wolff@kdab.com>2017-06-01 23:00:21 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-06-05 14:18:03 -0300
commit5ea0416f51cc93436bbe497c62ab49fd9cb245b6 (patch)
tree931608caf53e6c45bbb8f38b89cc34f03d958455 /tools
parent6db47fdec7562b02703e346c10f7f4efdda6af5a (diff)
perf report: Include partial stacks unwound with libdw
So far the whole stack was thrown away when any error occurred before the maximum stack depth was unwound. This is actually a very common scenario though. The stacks that got unwound so far are still interesting. This removes a large chunk of differences when comparing perf script output for libunwind and libdw perf unwinding. E.g. with libunwind: ~~~~~ heaptrack_gui 2228 135073.388524: 479408 cycles: ffffffff811749ed perf_iterate_ctx ([kernel.kallsyms]) ffffffff81181662 perf_event_mmap ([kernel.kallsyms]) ffffffff811cf5ed mmap_region ([kernel.kallsyms]) ffffffff811cfe6b do_mmap ([kernel.kallsyms]) ffffffff811b0dca vm_mmap_pgoff ([kernel.kallsyms]) ffffffff811cdb0c sys_mmap_pgoff ([kernel.kallsyms]) ffffffff81033acb sys_mmap ([kernel.kallsyms]) ffffffff81631d37 entry_SYSCALL_64_fastpath ([kernel.kallsyms]) 192ca mmap64 (/usr/lib/ld-2.25.so) 59a9 _dl_map_object_from_fd (/usr/lib/ld-2.25.so) 83d0 _dl_map_object (/usr/lib/ld-2.25.so) cda1 openaux (/usr/lib/ld-2.25.so) 1834f _dl_catch_error (/usr/lib/ld-2.25.so) cfe2 _dl_map_object_deps (/usr/lib/ld-2.25.so) 3481 dl_main (/usr/lib/ld-2.25.so) 17387 _dl_sysdep_start (/usr/lib/ld-2.25.so) 4d37 _dl_start (/usr/lib/ld-2.25.so) d87 _start (/usr/lib/ld-2.25.so) heaptrack_gui 2228 135073.388677: 611329 cycles: 1a3e0 strcmp (/usr/lib/ld-2.25.so) 82b2 _dl_map_object (/usr/lib/ld-2.25.so) cda1 openaux (/usr/lib/ld-2.25.so) 1834f _dl_catch_error (/usr/lib/ld-2.25.so) cfe2 _dl_map_object_deps (/usr/lib/ld-2.25.so) 3481 dl_main (/usr/lib/ld-2.25.so) 17387 _dl_sysdep_start (/usr/lib/ld-2.25.so) 4d37 _dl_start (/usr/lib/ld-2.25.so) d87 _start (/usr/lib/ld-2.25.so) ~~~~~ With libdw without this patch: ~~~~~ heaptrack_gui 2228 135073.388524: 479408 cycles: ffffffff811749ed perf_iterate_ctx ([kernel.kallsyms]) ffffffff81181662 perf_event_mmap ([kernel.kallsyms]) ffffffff811cf5ed mmap_region ([kernel.kallsyms]) ffffffff811cfe6b do_mmap ([kernel.kallsyms]) ffffffff811b0dca vm_mmap_pgoff ([kernel.kallsyms]) ffffffff811cdb0c sys_mmap_pgoff ([kernel.kallsyms]) ffffffff81033acb sys_mmap ([kernel.kallsyms]) ffffffff81631d37 entry_SYSCALL_64_fastpath ([kernel.kallsyms]) heaptrack_gui 2228 135073.388677: 611329 cycles: ~~~~~ With this patch applied, the libdw unwinder will produce the same output as the libunwind unwinder. Signed-off-by: Milian Wolff <milian.wolff@kdab.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/20170601210021.20046-1-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/unwind-libdw.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index 943a06291587..b4c20124d2ee 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -224,7 +224,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui);
- if (err && !ui->max_stack)
+ if (err && ui->max_stack != max_stack)
err = 0;
/*

Privacy Policy