• Kan Liang's avatar
    perf diff: Do not overwrite valid build id · ed6c166c
    Kan Liang authored
    Fixes a perf diff regression issue which was introduced by commit
    5baecbcd ("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: default avatarKan 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: 5baecbcd ("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.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    ed6c166c
symbol.c 46.9 KB