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5ea0416f51
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>
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|---|---|---|
| .. | ||
| arch | ||
| bench | ||
| Documentation | ||
| jvmti | ||
| pmu-events | ||
| python | ||
| scripts | ||
| tests | ||
| trace | ||
| ui | ||
| util | ||
| .gitignore | ||
| Build | ||
| builtin-annotate.c | ||
| builtin-bench.c | ||
| builtin-buildid-cache.c | ||
| builtin-buildid-list.c | ||
| builtin-c2c.c | ||
| builtin-config.c | ||
| builtin-data.c | ||
| builtin-diff.c | ||
| builtin-evlist.c | ||
| builtin-ftrace.c | ||
| builtin-help.c | ||
| builtin-inject.c | ||
| builtin-kallsyms.c | ||
| builtin-kmem.c | ||
| builtin-kvm.c | ||
| builtin-list.c | ||
| builtin-lock.c | ||
| builtin-mem.c | ||
| builtin-probe.c | ||
| builtin-record.c | ||
| builtin-report.c | ||
| builtin-sched.c | ||
| builtin-script.c | ||
| builtin-stat.c | ||
| builtin-timechart.c | ||
| builtin-top.c | ||
| builtin-trace.c | ||
| builtin-version.c | ||
| builtin.h | ||
| check-headers.sh | ||
| command-list.txt | ||
| CREDITS | ||
| design.txt | ||
| Makefile | ||
| Makefile.config | ||
| Makefile.perf | ||
| MANIFEST | ||
| perf-archive.sh | ||
| perf-completion.sh | ||
| perf-read-vdso.c | ||
| perf-sys.h | ||
| perf-with-kcore.sh | ||
| perf.c | ||
| perf.h | ||