Thread performance and tuning

To help you set the maximum number of threads that are permitted per process for any application that uses threads, data is collected in the following fields in the System Summary Report:
  • MAXIMUM THREADS PER PROCESS

    The maximum number of threads active in any process during the data collection interval. Only processes that created at least 1 thread during the data collection interval are considered for this value. If no threads were created for any process during the data collection interval, then this value is 0. For example, assume there is only 1 process containing 5 threads before the data collection interval. If 1 new thread is created during the interval, this value is set to 6. If no new threads are created during the interval, this value is 0.

  • HIGH WATER MARK NUMBER OF THREADS ACTIVE IN A PROCESS

    The maximum number of threads active in any process at any point in time during the current system initial program load (IPL).

  • THREAD CREATION RATE

    The number of threads that are created per second during an iteration of data collection.

  • THREADED PROCESSES CREATED DURING DATA COLLECTION

    The total number of processes that were created during an iteration of data collection.

The minimum, maximum, and mean thread creation rates per process are displayed in the System Summary report in the THREADED PROCESS SUMMARY REPORT (THREADS PER PROCESS PER SECOND) table. The following data is shown in this table:
  • PID

    The process ID of the thread. An entry of OTHER refers to the thread creation rate per process for all other processes (including those started when the data collection was already running) that are not individually identified by PID. Rates are shown for the run time of the data collection; that is, this number is equal to: (THREAD CREATION RATE/THREADED PROCESSES CREATED DURING DATA COLLECTION) less the data for named entries in the table.

  • NAME

    The trace name of the program. Named entries are displayed for threaded processes that existed when data collection started; these rates are shown for the life of the process.

  • MIN/MAX/MEAN

    The minimum, maximum, and mean thread creation rates per process.

If a thread application is using a large number of threads compared to the number defined in keypoint A (CTKA), you can enter the ZCTKA ALTER command to change the maximum number of threads.