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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|---|---|---|
| Documentation | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.