• Jin Yao's avatar
    perf stat: Disable the NMI watchdog message on hybrid · 493be70a
    Jin Yao authored
    If we run a single workload that only runs on big core, there is always
    a ugly message about disabling the NMI watchdog because the atom is not
    counted.
    
    Before:
    
      # ./perf stat true
    
       Performance counter stats for 'true':
    
                    0.43 msec task-clock                #    0.396 CPUs utilized
                       0      context-switches          #    0.000 /sec
                       0      cpu-migrations            #    0.000 /sec
                      45      page-faults               #  103.918 K/sec
                 639,634      cpu_core/cycles/          #    1.477 G/sec
           <not counted>      cpu_atom/cycles/                                              (0.00%)
                 643,498      cpu_core/instructions/    #    1.486 G/sec
           <not counted>      cpu_atom/instructions/                                        (0.00%)
                 123,715      cpu_core/branches/        #  285.694 M/sec
           <not counted>      cpu_atom/branches/                                            (0.00%)
                   4,094      cpu_core/branch-misses/   #    9.454 M/sec
           <not counted>      cpu_atom/branch-misses/                                       (0.00%)
    
             0.001092407 seconds time elapsed
    
             0.001144000 seconds user
             0.000000000 seconds sys
    
      Some events weren't counted. Try disabling the NMI watchdog:
              echo 0 > /proc/sys/kernel/nmi_watchdog
              perf stat ...
              echo 1 > /proc/sys/kernel/nmi_watchdog
    
      # ./perf stat -e '{cpu_atom/cycles/,msr/tsc/}' true
    
       Performance counter stats for 'true':
    
           <not counted>      cpu_atom/cycles/                                              (0.00%)
           <not counted>      msr/tsc/                                                      (0.00%)
    
             0.001904106 seconds time elapsed
    
             0.001947000 seconds user
             0.000000000 seconds sys
    
      Some events weren't counted. Try disabling the NMI watchdog:
              echo 0 > /proc/sys/kernel/nmi_watchdog
              perf stat ...
              echo 1 > /proc/sys/kernel/nmi_watchdog
      The events in group usually have to be from the same PMU. Try reorganizing the group.
    
    Now we disable the NMI watchdog message on hybrid, otherwise there
    are too many false positives.
    
    After:
    
      # ./perf stat true
    
       Performance counter stats for 'true':
    
                    0.79 msec task-clock                #    0.419 CPUs utilized
                       0      context-switches          #    0.000 /sec
                       0      cpu-migrations            #    0.000 /sec
                      48      page-faults               #   60.889 K/sec
                 777,692      cpu_core/cycles/          #  986.519 M/sec
           <not counted>      cpu_atom/cycles/                                              (0.00%)
                 669,147      cpu_core/instructions/    #  848.828 M/sec
           <not counted>      cpu_atom/instructions/                                        (0.00%)
                 128,635      cpu_core/branches/        #  163.176 M/sec
           <not counted>      cpu_atom/branches/                                            (0.00%)
                   4,089      cpu_core/branch-misses/   #    5.187 M/sec
           <not counted>      cpu_atom/branch-misses/                                       (0.00%)
    
             0.001880649 seconds time elapsed
    
             0.001935000 seconds user
             0.000000000 seconds sys
    
      # ./perf stat -e '{cpu_atom/cycles/,msr/tsc/}' true
    
       Performance counter stats for 'true':
    
           <not counted>      cpu_atom/cycles/                                              (0.00%)
           <not counted>      msr/tsc/                                                      (0.00%)
    
             0.000963319 seconds time elapsed
    
             0.000999000 seconds user
             0.000000000 seconds sys
    Signed-off-by: default avatarJin Yao <yao.jin@linux.intel.com>
    Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: Jin Yao <yao.jin@intel.com>
    Cc: Kan Liang <kan.liang@linux.intel.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: http://lore.kernel.org/lkml/20210610034557.29766-1-yao.jin@linux.intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    493be70a
stat-display.c 32.1 KB