Commit-ID: f1f13af99a903ae873f5373e965508e0486c1c29 Gitweb: http://git.kernel.org/tip/f1f13af99a903ae873f5373e965508e0486c1c29 Author: Namhyung Kim <namhy...@kernel.org> AuthorDate: Thu, 29 Jan 2015 17:07:21 +0900 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Thu, 29 Jan 2015 16:20:42 -0300
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 <namhy...@kernel.org> Cc: Adrian Hunter <adrian.hun...@intel.com> Cc: Andi Kleen <a...@firstfloor.org> Cc: David Ahern <dsah...@gmail.com> Cc: Frederic Weisbecker <fweis...@gmail.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Stephane Eranian <eran...@google.com> Link: http://lkml.kernel.org/r/1422518843-25818-41-git-send-email-namhy...@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/dso.h | 1 + tools/perf/util/unwind-libunwind.c | 31 ++++++++++++++++++++----------- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h index 3782c82..ced9284 100644 --- a/tools/perf/util/dso.h +++ b/tools/perf/util/dso.h @@ -139,6 +139,7 @@ struct dso { u32 status_seen; size_t file_size; struct list_head open_entry; + u64 frame_offset; } data; union { /* Tool specific area */ diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c index 6edf535..e3c40a5 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
