• Andi Kleen's avatar
    perf/x86: Export some PMU attributes in caps/ directory · b00233b5
    Andi Kleen authored
    It can be difficult to figure out for user programs what features
    the x86 CPU PMU driver actually supports. Currently it requires
    grepping in dmesg, but dmesg is not always available.
    
    This adds a caps directory to /sys/bus/event_source/devices/cpu/,
    similar to the caps already used on intel_pt, which can be used to
    discover the available capabilities cleanly.
    
    Three capabilities are defined:
    
     - pmu_name:	Underlying CPU name known to the driver
     - max_precise:	Max precise level supported
     - branches:	Known depth of LBR.
    
    Example:
    
      % grep . /sys/bus/event_source/devices/cpu/caps/*
      /sys/bus/event_source/devices/cpu/caps/branches:32
      /sys/bus/event_source/devices/cpu/caps/max_precise:3
      /sys/bus/event_source/devices/cpu/caps/pmu_name:skylake
    Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
    Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Link: http://lkml.kernel.org/r/20170822185201.9261-3-andi@firstfloor.orgSigned-off-by: Ingo Molnar's avatarIngo Molnar <mingo@kernel.org>
    b00233b5
core.c 59.3 KB