• Namhyung Kim's avatar
    perf stat: Use cpu-clock event for cpu targets · a1f3d567
    Namhyung Kim authored
    Currently 'perf stat' always counts task-clock event by default.  But
    it's somewhat confusing for system-wide targets (especially with 'sleep
    N' as the 'sleep' task just sleeps and doesn't use cputime).  Changing
    to cpu-clock event instead for that case makes more sense IMHO.
    
    Before:
      # perf stat -a sleep 0.1
    
       Performance counter stats for 'system wide':
    
            403.038603      task-clock (msec)     #    4.001 CPUs utilized
                   150      context-switches      #    0.372 K/sec
                     7      cpu-migrations        #    0.017 K/sec
                    71      page-faults           #    0.176 K/sec
            23,705,169      cycles                #    0.059 GHz
            15,888,166      instructions          #    0.67  insn per cycle
             3,326,078      branches              #    8.253 M/sec
                87,643      branch-misses         #    2.64% of all branches
    
           0.100737009 seconds time elapsed
    
      #
    
    After:
    
      # perf stat -a sleep 0.1
    
       Performance counter stats for 'system wide':
    
            404.271182      cpu-clock (msec)      #    4.000 CPUs utilized
                   143      context-switches      #    0.354 K/sec
                    13      cpu-migrations        #    0.032 K/sec
                    73      page-faults           #    0.181 K/sec
            22,119,220      cycles                #    0.055 GHz
            13,622,065      instructions          #    0.62  insn per cycle
             2,918,769      branches              #    7.220 M/sec
                85,033      branch-misses         #    2.91% of all branches
    
           0.101073089 seconds time elapsed
    
      #
    Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
    Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Andi Kleen <andi@firstfloor.org>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Link: http://lkml.kernel.org/r/1463119263-5569-3-git-send-email-namhyung@kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    a1f3d567
builtin-stat.c 59.3 KB