• Stephane Eranian's avatar
    tools/perf/stat: Add event unit and scale support · 410136f5
    Stephane Eranian authored
    This patch adds perf stat support for handling event units and
    scales as exported by the kernel.
    
    The kernel can export PMU events actual unit and scaling factor
    via sysfs:
    
      $ ls -1 /sys/devices/power/events/energy-*
      /sys/devices/power/events/energy-cores
      /sys/devices/power/events/energy-cores.scale
      /sys/devices/power/events/energy-cores.unit
      /sys/devices/power/events/energy-pkg
      /sys/devices/power/events/energy-pkg.scale
      /sys/devices/power/events/energy-pkg.unit
      $ cat /sys/devices/power/events/energy-cores.scale
      2.3283064365386962890625e-10
      $ cat cat /sys/devices/power/events/energy-cores.unit
      Joules
    
    This patch modifies the pmu event alias code to check
    for the presence of the .unit and .scale files to load
    the corresponding values. They are then used by perf stat
    transparently:
    
       # perf stat -a -e power/energy-pkg/,power/energy-cores/,cycles -I 1000 sleep 1000
       #          time             counts   unit events
           1.000214717               3.07 Joules power/energy-pkg/         [100.00%]
           1.000214717               0.53 Joules power/energy-cores/
           1.000214717           12965028        cycles                    [100.00%]
           2.000749289               3.01 Joules power/energy-pkg/
           2.000749289               0.52 Joules power/energy-cores/
           2.000749289           15817043        cycles
    
    When the event does not have an explicit unit exported by
    the kernel, nothing is printed. In csv output mode, there
    will be an empty field.
    
    Special thanks to Jiri for providing the supporting code
    in the parser to trigger reading of the scale and unit files.
    Signed-off-by: default avatarStephane Eranian <eranian@google.com>
    Reviewed-by: default avatarJiri Olsa <jolsa@redhat.com>
    Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
    Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
    Cc: zheng.z.yan@intel.com
    Cc: bp@alien8.de
    Cc: maria.n.dimakopoulou@gmail.com
    Cc: acme@redhat.com
    Link: http://lkml.kernel.org/r/1384275531-10892-3-git-send-email-eranian@google.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    410136f5
builtin-stat.c 47.1 KB