• Namhyung Kim's avatar
    perf record: Show precise number of samples · e3d59112
    Namhyung Kim authored
    After perf record finishes, it prints file size and number of samples in
    the file but this info is wrong since it assumes typical sample size of
    24 bytes and divides file size by the value.
    
    However as we post-process recorded samples for build-id, it can show
    correct number like below.  If build-id post-processing is not requested
    just omit the wrong number of samples.
    
      $ perf record noploop 1
        [ perf record: Woken up 1 times to write data ]
        [ perf record: Captured and wrote 0.159 MB perf.data (3989 samples) ]
    
      $ perf report --stdio -n
      # To display the perf.data header info, please use --header/--header-only options.
      #
      # Samples: 3K of event 'cycles'
      # Event count (approx.): 3771330663
      #
      # Overhead       Samples  Command  Shared Object     Symbol
      # ........  ............  .......  ................  ..........................
      #
          99.90%          3982  noploop  noploop           [.] main
           0.09%             1  noploop  ld-2.17.so        [.] _dl_check_map_versions
           0.01%             1  noploop  [kernel.vmlinux]  [k] setup_arg_pages
           0.00%             5  noploop  [kernel.vmlinux]  [k] intel_pmu_enable_all
    Reported-by: default avatarMilian Wolff <mail@milianw.de>
    Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
    Reviewed-by: default avatarJiri Olsa <jolsa@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: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Stephane Eranian <eranian@google.com>
    Link: http://lkml.kernel.org/r/1422518843-25818-4-git-send-email-namhyung@kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    e3d59112
builtin-record.c 24 KB