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WebSphere MQ and UNIX Process Priority

 

This information applies to WebSphere MQ running on UNIX systems only.

If you run a process in the background, that process can be given a higher nice value (and hence lower priority) by the invoking shell. This might have general WebSphere MQ performance implications. In highly-stressed situations, if there are many ready-to-run threads at a higher priority and some at a lower priority, operating system scheduling characteristics can deprive the lower priority threads of CPU time.

It is strongly recommended that independently started processes associated with queue managers, such as runmqlsr, have the same nice values as the queue manager they are associated with. Ensure the shell does not assign a higher nice value to these background processes. For example, in ksh, use the setting "set +o bgnice" to stop ksh from raising the nice value of background processes. We can verify the nice values of running processes by examining the NI column of a "ps -efl" listing.

It is also recommended that you start WebSphere MQ application processes with the same nice value as the queue manager. If they run with different nice values, an application thread might block a queue manager thread, or vice versa, causing performance to degrade.

 

Parent topic:

System Administration Guide


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