IV53199: UNIX OS AGENT PROCESS.CPU_PCT ATTRIBUTE VALUE IS INACCURATE

IBM Tivoli Monitoring: Unix(R) OS Agent 6.3.0.2-TIV-ITM_UNIX-IF0006
IBM Tivoli Monitoring 6.3.0 Fix Pack 3 (6.3.0-TIV-ITM-FP0003)

APAR status

• Closed as program error.

Error description

• According to the current algorithm the CPU_Pct attribute is
  normalized
  to the integer number of online logical CPUs. This is not
  aligned to
  what AIX Premium agent and the topas command do, which is a
  normalization to the actual CPU entitlement of the LPAR where
  the
  process is running.
  
  
   Affected Platforms / Versions:
     This issue affects the UNIX OS Agent running on AIX only.
     This issue affects the UNIX OS Agent version 6.30 or later.
  
   Diagnostics:
     increase KBB_RAS1 to include (UNIT:proc ALL), then check how
  CPU pct
     gets calculated in the calculateCPUPercentage method.
  
   Example:
   (52A75D2A.0006-4:procusage.cpp,81,"getNcpus") Number of
  configured CPUs:
    4, online: 4
   .....
   (52A75D2A.000F-4:procusage.cpp,113,"calculateCPUPercentage")
  Pid
   1573006, Delta process time 60516637000, Delta CPU: 15329767
  
   , CPU pct: 0.633287
  
  
   here the applied normalization factor can be derived by
  formula:
   N = (10000 * Delta CPU) / (Delta process time * CPU pct)
   which evaluates 4, given the above sample values. This is the
   number of online CPUs in getNcpus method, and may not
  correspond to the
   entitlement displayed by the lparstat command.
  
  
   Initial Impact:
   Medium, single attribute not accurate enough
  
   Additional Keywords:
   UNIXPS
   CPUPERCENT
  

Local fix

Problem summary

• Monitoring Agent for UNIX OS CPU Pct attribute in the Process
  attribute group not in synch with AIX topas and nmon tools.
  
  
  The Monitoring Agent for UNIX OS is aligned to the command "ps
  -p <PID> -o pcu" when reporting CPU utilization of processes in
  the CPU Pct attribute of the Process attribute group.  This
  value is normalized to the number of online logical processors
  and may be largely different from what the topas and nmon tools
  display on AIX.  Topas normalizes  processes' CPU utilization to
  the LPAR entitlement, if in a shared capped or dedicated
  configuration, or to the actual current physical processors'
  consumption, if in a shared uncapped configuration.  Nmon does
  not apply any normalization, so values can exceed 100%.
  
  In order for this APAR to be properly implemented in your
  environment, a new environment variable has been added.  See the
  "Install Actions" section of the APAR conclusion for more
  details.
  

Problem conclusion

• Install Actions:
  
  A new environment variable has been added,
  KUX_PROC_CPU_NORMALIZE, with two allowed values, 'topas' and
  'nmon', to change agent behavior and align it to topas and nmon
  tools respectively.  Default behavior is unchanged.
  
  
  The fix for this APAR is contained in the following maintenance
  packages:
  
     | fix pack | 6.3.0-TIV-ITM-FP0003
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  ITM AGENT UNIX

• Fixed component ID

  5724C040U

Applicable component levels

• R630 PSY

     UP

• R610 PSN

     UP

• R620 PSN

     UP

• R621 PSN

     UP

• R622 PSN

     UP

• R623 PSN

     UP