IJ27711: MUTEX CONTENTION AND HIGH CPU USAGE

APAR status

• Closed as program error.

Error description

• When a metanode receives many RPC
  requests from the clients nodes,
  it is possible for mutex
  contention to occur which in turn
  can lead to high CPU usage.
  This could happen when
  many nodes share access to the
  same file/directory such as the
  root directory of the file system.
  

Local fix

• Setting preferDesignatedMnode
  configuration variable to 1
  Setting mnodeRemoteAccessThreadhold
  configuration variable to 0
  

Problem summary

• When a metanode receives many RPC
  requests from the clients nodes,
  it is possible for mutex
  contention to occur which in turn
  can lead to high CPU usage.
  This could happen when
  many nodes share access to the
  same file/directory such as the
  root directory of the file system.
  

Problem conclusion

• Benefits of the solution:
  No more mutex contention that can lead to
  high CPU usage.
  
  Work Around:
  Setting preferDesignatedMnode
  configuration variable to 1
  Setting mnodeRemoteAccessThreadhold
  configuration variable to 0
  
  Problem trigger:
  Many nodes share read access to same
  file and or directory
  
  Symptom:
  Performance Impact/Degradation
  
  Platforms affected:
  ALL Operating System environments
  
  Functional Area affected:
  All Scale Users
  
  Customer Impact:
  High Importance
  

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:

  IJ27814

Fix information

• Fixed component name

  SPEC SCALE STD

• Fixed component ID

  5737F33AP

Applicable component levels