• Namhyung Kim's avatar
    perf test: Skip metrics w/o event name in stat STD output linter · 4d60e83d
    Namhyung Kim authored
    This test checks if the output of perf stat to match event names and
    metrics.  So it wants the output lines to have both event name and
    metric.  Otherwise it should skip the line.
    
    On AMD machines, the instruction event has two metrics and they are printed
    in separate lines.  It makes the line without event name like below:
    
      # perf stat -a sleep 1
    
       Performance counter stats for 'system wide':
    
               64,383.34 msec cpu-clock                  #   64.048 CPUs utilized
                  14,526      context-switches           #  225.617 /sec
                     112      cpu-migrations             #    1.740 /sec
                     190      page-faults                #    2.951 /sec
             807,558,652      cycles                     #    0.013 GHz                         (83.30%)
              69,809,799      stalled-cycles-frontend    #    8.64% frontend cycles idle        (83.30%)
             196,983,266      stalled-cycles-backend     #   24.39% backend cycles idle         (83.30%)
             424,876,008      instructions               #    0.53  insn per cycle
     (here) --->                                  #    0.46  stalled cycles per insn     (83.30%)
              97,788,321      branches                   #    1.519 M/sec                       (83.34%)
               4,147,377      branch-misses              #    4.24% of all branches             (83.46%)
    
             1.005241409 seconds time elapsed
    
    Also modern Intel machines have TopDown metrics which also don't have
    event names.
    
      # perf stat -a sleep 1
    
       Performance counter stats for 'system wide':
    
                8,015.39 msec cpu-clock                        #    7.996 CPUs utilized
                   5,823      context-switches                 #  726.477 /sec
                     189      cpu-migrations                   #   23.580 /sec
                     139      page-faults                      #   17.342 /sec
             435,139,308      cycles                           #    0.054 GHz
             193,891,345      instructions                     #    0.45  insn per cycle
              42,773,028      branches                         #    5.336 M/sec
               2,298,113      branch-misses                    #    5.37% of all branches
                              TopdownL1                 #     25.5 %  tma_backend_bound
                  /-->                                  #      7.9 %  tma_bad_speculation
        (here) --+                                      #     55.7 %  tma_frontend_bound
                  \-->                                  #     10.9 %  tma_retiring
    
             1.002395924 seconds time elapsed
    
    There is a check to skip TopdownL1 and TopdownL2 specifically but it
    does not cover every affected lines.
    
    So there is another check to skip the line if it has nothing on the left
    side of # sign.  Well.. it seems ok but that's not enough too.
    
    When aggregation mode (like --per-socket or --per-thread) is used, it
    adds some prefix (e.g. CPU socket, task name and PID) in the output
    line.  So the test code ignores them to normalize result.
    
    A problem can happen for per-thread mode when task name contains one or
    more spaces.  It'd only ignore the first part of the task name, and it
    thinks there's something more in the line so it would not skip.
    
      # perf stat -a --perf-thread sleep 1
      ...
                perf-21276                  #     70.2 %  tma_backend_bound
                perf-21276                  #      3.9 %  tma_bad_speculation
                perf-21276                  #     10.5 %  tma_frontend_bound
                perf-21276                  #     15.3 %  tma_retiring
    	    ^^^^^^^^^^
    	    (ignored)
    
             my task-21328                  #     70.2 %  tma_backend_bound
             my task-21328                  #      3.9 %  tma_bad_speculation
             my task-21328                  #     10.5 %  tma_frontend_bound
             my task-21328                  #     15.3 %  tma_retiring
    	 ^^
         (ignored)
    
    So I think it should look at the metric names instead.  Add skip_metric
    to hold the list of names to skip.  It would contain 'stalled cycles per
    insn' and metrics started by 'tma_'.
    
    Fixes: 99a04a48 ("perf test: Add test case for the standard 'perf stat' output")
    Acked-by: default avatarIan Rogers <irogers@google.com>
    Cc: Kan Liang <kan.liang@linux.intel.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Ingo Molnar <mingo@kernel.org>
    Link: https://lore.kernel.org/r/20230623230139.985594-2-namhyung@kernel.orgSigned-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
    4d60e83d
stat+std_output.sh 2.78 KB