Re: 'crafty' took ages to kill

From: Robert Hyatt (hyatt_at_crafty.cis.uab.edu)
Date: 12/31/03 

Date: Wed, 31 Dec 2003 02:48:04 +0000 (UTC)

In rec.games.chess.computer Dr. David Kirkby <see_my_signature_for_my_real_address@hotmail.com> wrote:
> Sorry for the cross-posting to two quite different newsgroups, but it
> seems appropiate in the circumstances.

> 'crafty' is a well known chess program that can run on UNIX machines.
> I've just spent quite a while trying to 'kill' an unwanted 'crafty'
> process running on my UNIX worksation, which I noticed had eaten up
> some 61 hours of CPU time. Despite

> % kill pid

> then when that failed

> % kill -9 pid

> a couple of times, it would not die. Finally after about 5 kill -9's
> the process died. Has anyone seen this before? I'm running a Sun Ultra
> 80 workstation, Solaris 9, 4 x 450 MHz CPUs, 4 GB RAM, crafty 19.7
> built for multi-threaded operation.

Most likely you had a large hash table setting. The original kill
command probably caused Crafty to crash, which will then write a .core
file. With a big hash, egtb cache, egtb decompression indices, you can
get a .core file that will choke a large mule...

Otherwise no idea as a process can _never_ ignore kill -9...

> What can stop a process responding to SIGKILL ?? Since there were two
> copies of this process running (one intentional, one not intenstional)
> each configured to use 4 CPUs, the load average was about 8, but that
> should not be excessive for a quad processor machine. The machine did
> not appear under any strain, and interactive peformance was fine, so
> I'm a bit puzzled why this should happen.

> I've seen similar things before on a Sun and once a reboot was
> required. I'm just not quite sure how it can occur.

I don't see this on linux so I am not sure, but the most common problem
is the huge core file that can take forever to write, particularly if you
are using NFS for your directory.

> As usual, my email address can be found at
> http://atlc.sourceforge.net/contact.html
> should anyone choose to email me, although the newsgroup is probably a
> better place for a response. 

-- 
Robert M. Hyatt, Ph.D.          Computer and Information Sciences
hyatt@uab.edu                   University of Alabama at Birmingham
(205) 934-2213                  136A Campbell Hall
(205) 934-5473 FAX              Birmingham, AL 35294-1170