Difference between user and system mode
Article ID: 269182
Updated On:
Products
Issue/Introduction
In the IDMS Performance Monitor interval reports there are separate user and system mode CPU fields. What is the difference between User and system mode. What are examples of these two execution modes?
Environment
Release : 19.0
Resolution
The report fields are documented in section Report Samples (Interval Monitor)
System Mode CPU Amount of time during the interval that the DC/UCF system spent performing system services on behalf of tasks. The value is reported as seconds.
User Mode CPU Amount of time during the interval that user tasks spent in execution. The value is reported as seconds.
An example of User Mode CPU is time spend executing user written ADS dialog code or COBOL programs.
An example of System Mode CPU is time spent executing IDMS system code in any of the IDMS nucleus modules like IDMSDBMS, IDMSDBIO or any of the RHDCxxxx modules.
Any time a user program makes a request to IDMS like a database request or mapping request it switches from user mode to system mode before it executes IDMS system code.
Once the request has been processed by IDMS it switches back to user mode to continue executing user code.
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