How to kill a user space process

[limp]

Hi all!

I was wondering if there is a command in order to kill a user-space process regarding its PID number.

Thanks!

[kakariko81280]

The command you are after is "kill"

chris@angua:~$ sleep 60 &
[1] 9659
chris@angua:~$ ps
  PID TTY          TIME CMD
 9583 pts/1    00:00:00 bash
 9659 pts/1    00:00:00 sleep
 9660 pts/1    00:00:00 ps
chris@angua:~$ kill 9659
chris@angua:~$
[1]+  Terminated              sleep 60

This quick demo creates a long running sleep process (ok, 60 seconds, but close enough) and runs it in the background. Then, while it is running, it is killed by using it's PID. The last line is the background process reporting that it has completed and giving the reason.

If the process does not respond to a simple kill command then you can use "kill -9", however this is not recommended unless it is the only option because it does not give the command a chance to clean up what it was working on.

I think you can only kill your own processes unless you are root. The permissions may be more complex than that, but I've not really looked into it.

Let us know how you get on,

Chris...

[limp]

Thank for your reply!

I have tried to use "kill <PID>" or "kill -9 <PID>" but nothing happened.

I should notice at this point that I am using Linux on an embedded board.

Here are the running processes using the 'top' command:

  PID USER   STATUS     RSS  PPID %CPU %MEM COMMAND
    2 root     RWN        0     1 99.2  0.0 ksoftirqd/0
  269 root     R        388   255  0.5  1.3 top
    3 root     SW<        0     1  0.1  0.0 events/0
  255 root     S        420     1  0.0  1.4 sh
    1 root     S        348     0  0.0  1.2 init
  250 root     S        320     1  0.0  1.1 inetd
  246 root     S        312     1  0.0  1.0 udhcpc
  227 root     S        300     1  0.0  1.0 syslogd
  253 root     S        292     1  0.0  1.0 crond
  230 root     S        260     1  0.0  0.8 klogd
    4 root     SW<        0     1  0.0  0.0 khelper
   49 root     SW<        0     5  0.0  0.0 kseriod
   61 root     SW         0     5  0.0  0.0 pdflush
   62 root     SW         0     5  0.0  0.0 pdflush
   63 root     SW<        0     5  0.0  0.0 kswapd0
   64 root     SW<        0     5  0.0  0.0 aio/0
  159 root     SW         0     1  0.0  0.0 mtdblockd
    5 root     SW<        0     1  0.0  0.0 kthread
   44 root     SW<        0     5  0.0  0.0 kblockd/0
   47 root     SW<        0     5  0.0  0.0 khubd

My main purpose is to kill the "ksoftirq/0" process which spends more than 99% of the CPU load.

I read somewhere that this is a Linux kernel soft IRQ process and that high softirq loads can totally kill userland.
That's sounds reasonable to me because a process that uses more than 99% of the CPU doesn't leave any load for other processes to run.

Any help or suggestion would be more than welcomed.
Thank you.