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WRKSYSACT (Work with System Activity)

iSeries users say that the WRKSYSACT (Work with System Activity) command tops their list of favorite iSeries (AS/400) commands. members David Coady, Matt Radatti and Carter Chamberlain had nothing but good things to say about the WRKSYSACT (Work with System Activity) command.

David said you can't go past the WRKSYSACT command when your CPU utilization starts going through the roof. "I have found WRKSYSACT the best way to see what is grinding your system to a halt and from the screen that is displayed, you can go directly into various jobs to see what they are doing and to manage them accordingly. Another plus is that you have one point of administration --no one else can use this command while it is in use."

Matt said the display allows him to view and collect performance data in real time. This data is reported for any selected job or task that is currently active on the system. He uses the command when there seems to be a slowdown in system response time, and it will tell him the job or task that is currently taken up much of the CPU. He said he finds jobs that are looping this way along with runaway queries.

Carter further said, "WRKSYSACT will display some of the same 'stuff' that you will see if you WRKACTJOB and sort by CPU%, but with what I consider to be several significant differences."

  • WRKSYSACT shows both tasks and jobs, whereas WRKACTJOB will only show you the latter.
  • WRKSYSACT shows you, in a partitioned system, how many CPUs are on the physical system and, more important, how many are currently allocated to the partition you are in.
  • WRKSYSACT displays, for the elapsed time period you are working in, the average, minimum and maximum CPU utilization percentages for the time period.
  • WRKSYSACT lets you see the CFINT task and what it's up to.

Here are a few tips for using WRKSYSACT:

  • Tapping WRKSYSACT to collect performance data
    Anyone who has used the WRKSYSACT command can tell you how useful it is to identify jobs in real time that are using too many system resources, usually CPU. What you may not know is that you can also run WRKSYSACT in batch to collect data about how well your system is performing.
  • New option within the WRKSYSACT command
    In the WRKSYSACT command (starting in V5R2) there is a new option, "6 = wait detail". What does this do? expert John Blenkinsop explains.
  • Slow system performance
    If your system performance is very slow in an external application that seems to be doing a high number of AuxIO operations, how can you determine where the bottleneck is? Use the WRKSYSACT command.

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