Messages in this thread | | | From | Ian Rogers <> | Date | Fri, 29 Mar 2024 09:32:45 -0700 | Subject | Re: [PATCH 0/4] perf annotate: Use libcapstone as a disasssembler |
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On Thu, Mar 28, 2024 at 4:20 PM Namhyung Kim <namhyung@kernel.org> wrote: > > Hello, > > As we've added libcapstone support, it's natural to use it for perf annotate > as well. This change added the capstone support on x86 first. Other archs > can be added later (by someone who can verify it doesn't break things). > > For now it tries to use capstone (if available) before objdump. But it > doesn't support source file and line number info. So users should use the > objdump (by passing --objdump=PATH option) if they need them. For example, > this command line will keep the existing behavior (i.e. using objdump). > > # not to use capstone for disassembly > $ perf annotate --objdump=objdump > > The capstone uses LLVM objdump style output which is slightly different than > the GNU objdump. But it should not have differences besides that. I've > verified the result of data type profiling and it produced the same output > but gave me ~3x speedups. > > Thanks, > Namhyung
I wanted to see what -fsanitize=address would think of libcaptstone and no issues, so:
Tested-by: Ian Rogers <irogers@google.com>
Some thoughts: - it may be worth adding to the commit message in "perf annotate: Split out util/disasm.c" that there's no functional change, - we lack perf annotate testing, - it seems capstone should be opt-out rather than opt-in as a library dependency (given the performance delta and the objdump interactions are at best messy), - if libcapstone could solve our addr2line issues too this would be great :-).
Thanks, Ian
> Cc: Changbin Du <changbin.du@huawei.com> > > > Namhyung Kim (4): > perf annotate: Use ins__is_xxx() if possible > perf annotate: Add and use ins__is_nop() > perf annotate: Split out util/disasm.c > perf annotate: Use libcapstone to disassemble > > tools/perf/util/Build | 1 + > tools/perf/util/annotate.c | 1711 ++--------------------------------- > tools/perf/util/annotate.h | 59 +- > tools/perf/util/disasm.c | 1739 ++++++++++++++++++++++++++++++++++++ > tools/perf/util/disasm.h | 112 +++ > 5 files changed, 1914 insertions(+), 1708 deletions(-) > create mode 100644 tools/perf/util/disasm.c > create mode 100644 tools/perf/util/disasm.h > > -- > 2.44.0.478.gd926399ef9-goog >
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