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| author | Namhyung Kim <namhyung@kernel.org> | 2015-01-29 11:07:21 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2015-01-29 22:20:42 +0300 |
| commit | f1f13af99a903ae873f5373e965508e0486c1c29 (patch) | |
| tree | 183674eba3f82637bc6270ac15960cf6e31fa9c2 /tools/perf/util/unwind-libunwind.c | |
| parent | 459a3df76c99124fd222586be7f10f862547e7a9 (diff) | |
| download | linux-f1f13af99a903ae873f5373e965508e0486c1c29.tar.xz | |
perf callchain: Cache eh/debug frame offset for dwarf unwind
When libunwind tries to resolve callchains it needs to know the offset
of .eh_frame_hdr or .debug_frame to access the dso.
Since it will always return the same result for a given DSO, just cache
the result as an optimization.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1422518843-25818-41-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/unwind-libunwind.c')
| -rw-r--r-- | tools/perf/util/unwind-libunwind.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c index 6edf535f65c2..e3c40a520a25 100644 --- a/tools/perf/util/unwind-libunwind.c +++ b/tools/perf/util/unwind-libunwind.c @@ -266,14 +266,17 @@ static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine, u64 *fde_count) { int ret = -EINVAL, fd; - u64 offset; + u64 offset = dso->data.frame_offset; - fd = dso__data_fd(dso, machine); - if (fd < 0) - return -EINVAL; + if (offset == 0) { + fd = dso__data_fd(dso, machine); + if (fd < 0) + return -EINVAL; - /* Check the .eh_frame section for unwinding info */ - offset = elf_section_offset(fd, ".eh_frame_hdr"); + /* Check the .eh_frame section for unwinding info */ + offset = elf_section_offset(fd, ".eh_frame_hdr"); + dso->data.frame_offset = offset; + } if (offset) ret = unwind_spec_ehframe(dso, machine, offset, @@ -287,14 +290,20 @@ static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine, static int read_unwind_spec_debug_frame(struct dso *dso, struct machine *machine, u64 *offset) { - int fd = dso__data_fd(dso, machine); + int fd; + u64 ofs = dso->data.frame_offset; - if (fd < 0) - return -EINVAL; + if (ofs == 0) { + fd = dso__data_fd(dso, machine); + if (fd < 0) + return -EINVAL; - /* Check the .debug_frame section for unwinding info */ - *offset = elf_section_offset(fd, ".debug_frame"); + /* Check the .debug_frame section for unwinding info */ + ofs = elf_section_offset(fd, ".debug_frame"); + dso->data.frame_offset = ofs; + } + *offset = ofs; if (*offset) return 0; |