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Limit the Size of Data Files

The Performance Agent System PC Analysis facility collects a significant amount of data. Therefore, log files can get rather large. It is recommended that collections be limited to under 15 minutes for most investigations.

As another example, the following command starts collecting system-wide PC statistics for all active processes at the default collection interval of 1 tick (10 milliseconds) and writes data to the PC log file SYSTEM.PCS in directory [ACCOUNT] on disk device DISK$. The collection terminates after the default period of 15 minutes.

$ ADVISE COLLECT SYSTEM_PC/OUTPUT=DISK$:[ACCOUNT]SYSTEM.PCS

There can be only one process on your system at any given time collecting system-wide PC data. If such a process already exists when you give the above command, no new PC data collection image is started, and you receive the message:

%PSDC-F-PCSAMPACT, PC sampling is currently active

You can stop your system-wide PC collection process at any time by entering CTRL+Y, or with the DCL STOP command issued from another process.

$ ADVISE COLLECT SYSTEM_PC/OUTPUT=PC.DAT Interrupt;
 CTRL+Y was typed here
$

When you type a CTRL+Y, the PC log file is closed. To resume the collection process, type the DCL CONTINUE command before entering a command that runs a different image. If the CONTINUE command is used, no new version of the log file is created.

You can inquire on the system-wide PC data collection process by typing CTRL+T at the terminal from which it is running, or by using the DCL command SHOW PROCESS from another terminal.