System Administration Guide: Advanced Administration

Troubleshooting Problems With System Processes

Here are some tips on obvious problems you might find:

Look for several identical jobs that are owned by the same user. This problem might occur because of a running script that starts a lot of background jobs without waiting for any of the jobs to finish.
Look for a process that has accumulated a large amount of CPU time. You can identify this problem by checking the TIME field in the ps output. Possibly, the process is in an endless loop.
Look for a process that is running with a priority that is too high. Use the ps -c command to see the CLS field, which displays the scheduling class of each process. A process executing as a real-time (RT) process can monopolize the CPU. Or, look for a timesharing (TS) process with a high nice number. A user with superuser privileges might have increased the prioritys of a process. The system administrator can lower the priority by using the nice command.
Look for a runaway process. A runaway process progressively uses more and more CPU time. You can identify this problem by looking at the time when the process started (STIME) and by watching the cumulation of CPU time (TIME) for a while.


23. Managing System Processes (Tasks) Managing Process Class Information How to Change the Priority of a Process


	Troubleshooting Problems With System Processes Here are some tips on obvious problems you might find: Look for several identical jobs that are owned by the same user. This problem might occur because of a running script that starts a lot of background jobs without waiting for any of the jobs to finish. Look for a process that has accumulated a large amount of CPU time. You can identify this problem by checking the `TIME` field in the `ps` output. Possibly, the process is in an endless loop. Look for a process that is running with a priority that is too high. Use the `ps -c` command to see the `CLS` field, which displays the scheduling class of each process. A process executing as a real-time (`RT`) process can monopolize the CPU. Or, look for a timesharing (`TS`) process with a high `nice` number. A user with superuser privileges might have increased the prioritys of a process. The system administrator can lower the priority by using the `nice` command. Look for a runaway process. A runaway process progressively uses more and more CPU time. You can identify this problem by looking at the time when the process started (`STIME`) and by watching the cumulation of CPU time (`TIME`) for a while.