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[Steve Langasek <steve.langasek@xxxxxxxxxxxxx>]

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https://bugs.launchpad.net/bugs/1560482

Title:
  perf: 24x7: Eliminate domain name suffix in event names

Status in linux package in Ubuntu:
  Confirmed

Bug description:
  Events in the 24x7 counters can belong to different domains like
  core, chip, virtual CPU home core, etc. To monitor an event, the
  user must specify the required parameters for the event, which
  include its name, the chip/core on which to monitor the event
  as well as the domain.

  Currently the event is specified to the perf tool as:

          'hv_24x7/HPM_0THRD_NON_IDLE_CCYC__PHYS_CORE,core=1/' \

  where the event name is 'HPM_0THRD_NON_IDLE_CCYC', the suffix
  '__PHYS_CORE' specifies the domain, and 'core=1' specifies the 
  core. This is inconsistent in that one parameter is specified
  as a suffix and the other in a parameter=value format.

  To simplify the usage, we can eliminate the suffix and let the 
  user specify the domain also in the param=value format. While
  the domain indices are "well known" or nearly fixed in value,
  we could display the domain indices in sysfs as a reference for 
  the users:

          $ cat /sys/bus/event_source/devices/hv_24x7/interface/domains
          1: Physical Chip
          2: Physical Core
          3: VCPU Home Core
          4: VCPU Home Chip
          5: VCPU Home Node
          6: VCPU Remote Node

  Using these the perf event can now be identified as

          hv_24x7/HPM_0THRD_NON_IDLE_CCYC,domain=2,core=1

  . This feature is implemented by the following commits which have now
  been merged into mainline:

          d34171e: powerpc/perf/hv-24x7: Display domain indices in sysfs
          8f69dc7: powerpc/perf/24x7: Eliminate domain suffix in event names

  == Comment: #1 - Sukadev Bhattiprolu <suka@xxxxxxxxxx> - 2016-03-21 15:26:33 ==
  Following two upstream commits are also related 24x7 and could
  be included in this feature:

  e5a5886: powerpc/perf/hv-24x7: Fix usage with chip events.
  2b206ee: powerpc/perf/hv-24x7: Display change in counter values

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