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authorKan Liang <kan.liang@intel.com>2016-12-13 10:29:44 -0500
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-12-20 12:00:38 -0300
commited6c166cc7dc329736cace3affd2df984fb22ec8 (patch)
tree45f700ec74fe62b6ac93923749eaba5def503ec7 /tools/perf
parentedee44be59190bf22d5c6e521f3852b7ff16862f (diff)
downloadlinux-ed6c166cc7dc329736cace3affd2df984fb22ec8.tar.bz2
perf diff: Do not overwrite valid build id
Fixes a perf diff regression issue which was introduced by commit 5baecbcd9c9a ("perf symbols: we can now read separate debug-info files based on a build ID") The binary name could be same when perf diff different binaries. Build id is used to distinguish between them. However, the previous patch assumes the same binary name has same build id. So it overwrites the build id according to the binary name, regardless of whether the build id is set or not. Check the has_build_id in dso__load. If the build id is already set, use it. Before the fix: $ perf diff 1.perf.data 2.perf.data # Event 'cycles' # # Baseline Delta Shared Object Symbol # ........ ....... ................ ............................. # 99.83% -99.80% tchain_edit [.] f2 0.12% +99.81% tchain_edit [.] f3 0.02% -0.01% [ixgbe] [k] ixgbe_read_reg After the fix: $ perf diff 1.perf.data 2.perf.data # Event 'cycles' # # Baseline Delta Shared Object Symbol # ........ ....... ................ ............................. # 99.83% +0.10% tchain_edit [.] f3 0.12% -0.08% tchain_edit [.] f2 Signed-off-by: Kan Liang <kan.liang@intel.com> Cc: Andi Kleen <andi@firstfloor.org> CC: Dima Kogan <dima@secretsauce.net> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Fixes: 5baecbcd9c9a ("perf symbols: we can now read separate debug-info files based on a build ID") Link: http://lkml.kernel.org/r/1481642984-13593-1-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/util/symbol.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index df2482b2ba45..dc93940de351 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1459,7 +1459,8 @@ int dso__load(struct dso *dso, struct map *map)
* Read the build id if possible. This is required for
* DSO_BINARY_TYPE__BUILDID_DEBUGINFO to work
*/
- if (is_regular_file(dso->long_name) &&
+ if (!dso->has_build_id &&
+ is_regular_file(dso->long_name) &&
filename__read_build_id(dso->long_name, build_id, BUILD_ID_SIZE) > 0)
dso__set_build_id(dso, build_id);