RE: [Fwd: fixing the Richmond cluster]

["Stefanovski, Sasko" <sstefano@richmond.edu>]

Jerry,

Thursday morning looks fine. Is it 9am ok?

I'll start looking at what we have on pscm1 tomorrow. Before doing any
compilation I would copy the source tree and play with the copy, so we can
have a copy of the source directory with all configuration files intact as
they were the last time the kernel was compiled. We can then play with our
copy. 

I agree that we should recompile the kernel at first to see if the process
would be right. After that we'll change the number of processes in the
tasks.h file and recompile again. 

Sasko

-----Original Message-----
From: gilfoyle [mailto:ggilfoyl@richmond.edu]
Sent: Monday, October 21, 2002 2:03 PM
To: Sashak Stafanovski
Subject: [Fwd: fixing the Richmond cluster]


hi sasko,

   i am forwarding the message i received from linuxlabs with
some guidance for recompiling the kernel on the cluster. it
lists where the configuration files are located which is 
important for us if we want to do this successfully. i've 
already done a couple of small things.

1. created backups on the disk of the different, existing 
versions of the kernel in the /boot/ area. look for files with
'-gpg' on the end.

2. modified /etc/lilo.conf to add a boot option 'URlinux' that
points to one of the backups i made above. the full file is
below.

i am glad to have you work on this, but i would like to be
around when you do it so i can learn more about it. would
Thursday morning be a good time?

i had the following thoughts on the plan for recompiling the
kernel. 

1. we should make a boot floppy in case disaster strikes.

2. we should recompile and test the kernel with NO changes
just to make sure the configuration files and such are accurate.

3. we should increase the parameter NR_TASKS to something like
3000 and MAX_TASKS_PER_USER to 1000 in
/usr/src/linux/include/tasks.h according to the reference below.

http://www.ltsp.org/documentation/lts_ig_v2.4/lts_ig_v2.4-14.html

http://www.geocrawler.com/archives/3/61/1998/10/0/2207294/

opps! i found tasks.h in /usr/src/linux/include/linux instead of
area described in the documentation. the file tasks.h is shown
below.

let me know what you think.

jerry


tasks.h ----------------------------------------

#ifndef _LINUX_TASKS_H
#define _LINUX_TASKS_H

/*
 * This is the maximum nr of tasks - change it if you need to
 */
 
#ifdef __SMP__
#define NR_CPUS 32              /* Max processors that can be running in
SMP */
#else
#define NR_CPUS 1
#endif

#define NR_TASKS        512     /* On x86 Max about 4000 */  <-- change
to 3000.

#define MAX_TASKS_PER_USER (NR_TASKS/2) <---- change to 1000.
#define MIN_TASKS_LEFT_FOR_ROOT 4


/*
 * This controls the maximum pid allocated to a process
 */
#define PID_MAX 0x8000

#endif


lilo.conf ----------------------------------------

boot=/dev/hda
map=/boot/map
install=/boot/boot.b
prompt
timeout=50
linear
default=linux

image=/boot/bzImage-2.2.20p7-pyro1-scyld-dolphin
        label=linux
        read-only
        root=/dev/hda1
        append="hdd=ide-scsi"

image=/boot/bzImage-2.2.17-lila.beosmp
        label=2-2-17
        append="mem=1024M"
        read-only
        root=/dev/hda1

image=/boot/bzImage-2.2.20p7-pyro1-scyld-dolphin-02-oct-21-gpg  /*
modified from here
        label=URlinux
        read-only
        root=/dev/hda1
        append="hdd=ide-scsi"


-- 
Dr. Gerard P. Gilfoyle
Physics Department                e-mail: ggilfoyl@richmond.edu
University of Richmond, VA 23173  phone:  804-289-8255
USA                               fax:    804-289-8482