User vs Kernel mode

Olivier Nicole on at
Tue Oct 17 02:52:36 UTC 2006

> Processes always start in kernel mode, because they're started by the
> kernel.  They typically spend most of their time in kernel mode (for
> example, whenever they're idle or waiting for I/O).  An active process
> may switch back and forward between kernel mode and user mode
> thousands of times a second.

Thanks for the clarification.

> Maybe you should describe your problem.
The application has been working fine for almost 3 years, along with
Apache, going through RELENG upgrade without problem.

Now I start noticing that Apache hangs (sig 11), either manually built
or port built, make buildworld hanged once with sig 11, my application
hangs with sig 11.

2 options:

- I added memory in the machine and the meory is causing problems.

- I changed my application a little bit and it started eating
  other processes.

Yesterday make buildworld consistenly hanged on building groff, today
after cleaning the memory (using plain rubber on DIMM contacts) it is
going fine (although Apache did hang since the cleaning).

So I'd like to be sure that my application cannot eat other processes,
so i could eliminate one cause.



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