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Kernel Idle

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Kernel Idle

I am not sure what the kernel idle process does. I have this process using up to 100% cpu time. Is this normal? It may be a stupid question, but can anybody tell me what the kerenel idle process is there for?
Ralf Puchner
Honored Contributor

Re: Kernel Idle

Kernel_idle is a standard OS process that should (must) be present on all
of your Tru64 UNIX systems.

If the system is doing nothing at all, then kernel_idle will absolutely be the top process. The top thread will be idle_thread. Cpus *cannot* be quiescent during periods of inactivity. So the kernel runs idle_thread to keep it happy. This does not indicate a performance problem. Any thread with real work to do will *always* preemp idle_thread.

kernel_idle tasks can be divided into 2 catagories:

system work - such as simple_lock() where the kernel is doing useful work on behalf processes that need things done, and

idle time - when the kernel has no work to do, so it runs the idle_thread.
Help() { FirstReadManual(urgently); Go_to_it;; }
Nicolas Dumeige
Esteemed Contributor

Re: Kernel Idle


It does remember M$ Windows System "Idle Process" !
Since NT was developped by the creator of OpenVMS, is the way of thinking OS idleness a DEC legacy ?


All different, all Unix
Victor Semaska
Frequent Advisor

Re: Kernel Idle

You may have a hardware problem. On one of our ES45s I noticed [kernel idle] at 100%. Further investigation showed that one of the 2 NICs in a NetRAIN device went bad. Use this command to look at all the threads running under [kernel idle]:

# ps -Am -O THREAD

This may help identify the problem. We were also experiencing poor response. How's the response on your system?

We're running Tru64 V5.1B PK3.