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Showing posts with label process. Show all posts
Showing posts with label process. Show all posts

Jul 18, 2011

Process states in linux systems

There are many states for processes in linux environment. You can see the process states using the following commands.

#ps
#ps -ax       -From all users and terminals.
#ps -aux     -Shows Process owner also.

For the dynamic details:

#top
#top -c      -Sorts according to CPU usage.
#top   and pressing M(shift+m)  - sorts according to memory usage.

Main process states are as follows:
D       Marks a process in disk (or other short term, uninterruptible) wait.
I        Marks a process that is idle (sleeping for longer than about 20 seconds).
R       Marks a runnable process.
S        Marks a process that is sleeping for less than about 20 seconds
T       Marks a stopped process.
Z       Marks a dead process (a ``zombie'').

Additional characters after these, indicates additional state information:

             +       The process is in the foreground process group of its control terminal.
             <       The process has raised CPU scheduling priority.
             >       The process has specified a soft limit on memory requirements and is currently           exceeding that limit; such a process is (necessarily) not swapped.
             E       The process is trying to exit.
             L       The process has pages locked in core (for example, for raw I/O).
             N       The process has reduced CPU scheduling priority (see setpriority(2)).
             s       The process is a session leader.
             V       The process is suspended during a vfork(2).
             W       The process is swapped out.
             X       The process is being traced or debugged.