[PATCH v7 00/14] Add support for remote unwind

From: He Kuang
Date: Tue May 31 2016 - 07:23:51 EST

v6 url:

Currently, perf script uses host unwind methods(local unwind) to parse
perf.data callchain info regardless of the target architecture. So we
get wrong result and no promotion when do remote unwind on other

This patchset checks whether a dso is 32-bit or 64-bit according to
elf class info for each thread to let perf use the correct remote
unwind methods instead.

Only x86 and aarch64 is added in this patchset to show the work flow,
other platforms can be added easily.

We can see the right result for unwind info on different machines, for
example: perf.data recorded on i686 qemu with '-g' option and parsed
on x86_64 machine.

before this patchset:

hello 1219 [001] 72190.667975: probe:sys_close: (c1169d60)
c1169d61 sys_close ([kernel.kallsyms])
c189c0d7 sysenter_past_esp ([kernel.kallsyms])
b777aba9 [unknown] ([vdso32])

(Add vdso into buildid-cache first by 'perf buildid-cache -a' and
libraries are provided in symfs dir)

hello 1219 [001] 72190.667975: probe:sys_close: (c1169d60)
c1169d61 sys_close ([kernel.kallsyms])
c189c0d7 sysenter_past_esp ([kernel.kallsyms])
b777aba9 __kernel_vsyscall ([vdso32])
b76971cc close (/lib/libc-2.22.so)
804842e fib (/tmp/hello)
804849d main (/tmp/hello)
b75d746e __libc_start_main (/lib/libc-2.22.so)
8048341 _start (/tmp/hello)

For using remote libunwind libraries, reference this:

and now we can use LIBUNWIND_DIR to specific custom dirctories
containing libunwind libs.

By following the advises from Jiri Olsa:

- Move unwind ops struct to unwind.h
- Add return value to function thread__insert_map()
- Split "Separate local/remote libunwind config" into two patches,
make commit message consistent with patch content.
- Move not supported warnings to "Support x86 target platform"
- Export $(ARCH)_unwind_libunwind_ops variables instead of
- Move arch/$(ARCH)/util/unwind-libunwind-$(ARCH).c into
util/libunwind/ folder.


He Kuang (14):
perf tools: Use LIBUNWIND_DIR for remote libunwind feature check
perf tools: Decouple thread->address_space on libunwind
perf tools: Introducing struct unwind_libunwind_ops for local unwind
perf tools: Move unwind__prepare_access from thread_new into
perf tools: Separate local/remote libunwind config
perf tools: Rename unwind-libunwind.c to unwind-libunwind-local.c
perf tools: Extract common API out of unwind-libunwind-local.c
perf tools: Export normalize_arch() function
perf tools: Check the target platform before assigning unwind methods
perf tools: Change fixed name of libunwind__arch_reg_id to macro
perf tools: Introduce flag to separate local/remote unwind compilation
perf callchain: Support x86 target platform
perf callchain: Support aarch64 cross-platform

tools/perf/arch/arm/util/Build | 2 +-
tools/perf/arch/arm64/util/Build | 2 +-
tools/perf/arch/arm64/util/unwind-libunwind.c | 4 +-
tools/perf/arch/common.c | 2 +-
tools/perf/arch/common.h | 1 +
tools/perf/arch/x86/util/Build | 2 +-
tools/perf/arch/x86/util/unwind-libunwind.c | 6 +-
tools/perf/config/Makefile | 53 +-
tools/perf/util/Build | 3 +
tools/perf/util/libunwind/arm64.c | 18 +
tools/perf/util/libunwind/x86_32.c | 18 +
tools/perf/util/machine.c | 10 +-
tools/perf/util/thread.c | 7 +-
tools/perf/util/thread.h | 9 +-
tools/perf/util/unwind-libunwind-local.c | 697 ++++++++++++++++++++++++++
tools/perf/util/unwind-libunwind.c | 694 ++-----------------------
tools/perf/util/unwind.h | 27 +-
17 files changed, 880 insertions(+), 675 deletions(-)
create mode 100644 tools/perf/util/libunwind/arm64.c
create mode 100644 tools/perf/util/libunwind/x86_32.c
create mode 100644 tools/perf/util/unwind-libunwind-local.c