[Bug 1893027] Re: [UBUNTU 20.04] lscpumf display raw event number incorrectly

[Andrew Cloke]

** Changed in: ubuntu-z-systems
       Status: In Progress => Fix Committed

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Title:
  [UBUNTU 20.04] lscpumf display raw event number incorrectly

Status in Ubuntu on IBM z Systems:
  Fix Committed
Status in s390-tools package in Ubuntu:
  Fix Released
Status in s390-tools source package in Focal:
  Fix Committed

Bug description:
  [Impact] 
   * lscpumf -c displays the raw counter number incorrectly
   * It is always displayed as rXXX (XXX being hex)
   * If PMU measurement facility device driver has been registered with a different type than PERF_TYPE_RAW(4) this is incorrect
   * It should be displayed as <type>:DDD (DDD being decimal)
   * Backported the fix to the legacy lscpumc perl tool. Newer version have converted this tool to C.

  [Test Case]
   * run lscpumf -c on IBM Z / s390x
   * verify output is 'rXXX' (XXX being hex) if type = PERF_TYPE_RAW(4)
   * verify output is '<type>:DDD' (DDD being decimal) if type != PERF_TYPE_RAW(4)

  To find out with PMU type number has been assigned to
  the PMU Measurement facility device driver, type command
  cat /sys/devices/cpum_cf/type (for counters)
  cat /sys/devices/cpum_cf/type (for sampling)

  [Regression Potential] 
   * regressions in lscpumf could break the visualization of CPU-measurement facilities on IBM Z
   * the package is only available on s390x and thus could only affect IBM Z machines

  [Other Info]
   * Needs to be tested/verified by IBM internally
   * Patch was provided by IBM
   * Related to LP: #1888231 and LP: #1892350
   * This patch is caused by upstream kernel commits: commit 6a82e23f45fe ("s390/cpumf: Adjust registration of s390 PMU device drivers") commit 66d258c5b048 ("perf/core: Optimize perf_init_event()")
   * Also fix the rename of counter CCERROR to CCFINISH caused by upstream kernel commit: commit 3d3af181d370 ("s390/cpum_cf,perf: change DFLT_CCERROR counter name")

  === Original Description ===
  Fix wrong output of lscpumf when device cpum_cf has different type than 4

  Please apply to ubuntu 20.04 (s390-tools version 2.12)

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