Collector Command

    Enables the collection of I/O services data. Data is collected
    for each I/O system service call in the program.

    Format

      SET IO_SERVICES

1  –  Description

    The SET IO_SERVICES command enables the collection of I/O system
    services data. After you enter the GO command with I/O data
    collection enabled, the Collector intercepts every I/O system
    service call during program execution. For each such call,
    the Collector gathers the appropriate information from the
    File Access Block (FAB), Record Access Block (RAB), or other
    parameters and records it in the performance data file. The exact
    information gathered depends on the I/O service, but will include
    the program address of the call, the name of the service, the CPU
    time stamp. It may also include the name of the file accessed,
    the record size of the transfer, the physical I/O read and write
    counts, and other information.

    You must collect stack PC information if you want to use a /MAIN_
    IMAGE, /CUMULATIVE or /STACK_DEPTH qualifier with the PLOT or
    TABULATE command in the Analyzer.

2  –  Qualifiers

2.1    /STACK_PCS

    Specifies that stack PC values are collected for I/O services
    data. This is the default upon entry into the Collector.

2.2    /NOSTACK_PCS

    Specifies that no stack PC values are collected for I/O services
    data.

2.3    /USER_ROUTINE

       /USER_ROUTINE=(image-name,entry-routine,exit-routine)
       /USER_ROUTINE=(image-name,entry-routine,)
       /USER_ROUTINE=(image-name,,exit-routine)

    Specifies that the specifed user routines shall be called at the
    start and end of each system service call.

    Qualifier Parameter         Description

    image-name                  The shareable image containing the
                                entry-routine or/and exit-routine.
    entry-routine               The routine to call before calling
                                the system service. The null string
                                (i.e. "") indicates no routine is to
                                be called.
    exit-routine                The routine to call after calling the
                                system service. The null string (i.e.
                                "") indicates no routine is to be
                                called.

    The following rule applies regarding the /USER_ROUTINE qualifier:

    1. Only one of the entry and exit routines may be null;

    For more information on user routines in PCA, see the HELP entry
    for User_Routines.

2.4    /NOUSER_ROUTINE

       /NOUSER_ROUTINE

    Specifies that no user routines shall be called at the start and
    end of each system service call. This is the default upon entry
    into the PCA Collector.

3  –  Examples

  PCAC> SET IO_SERVICES/STACK_PCS

      This command enables the collection of I/O services data, and
      specifies that stack PC values be collected.