topic Re: Assign a process to a processor in Operating System - HP-UX

Assign a process to a processor

Matteo Pignoni — Thu, 07 Jun 2001 19:27:53 GMT

Hi!
Is it possible to assign a process to a processor?
For example if I have a server with 4 processor, can I decide to execute a process only in the CPU #3 ?
Thanks.

Re: Assign a process to a processor

James R. Ferguson — Thu, 07 Jun 2001 19:32:36 GMT

Hi:

Take a look at PRM (Process Resource Manager) for this. Here's a link to the guide:

http://docs.hp.com/hpux/onlinedocs/B8733-90005/B8733-90005.html

...JRF...

Re: Assign a process to a processor

Patrick Wallek — Thu, 07 Jun 2001 20:06:53 GMT

Here's some more information on PRM. This includes pricing info.

http://www.software.hp.com/cgi-bin/swdepot_parser.cgi/cgi/displayProductInfo.pl?productNumber=B3835CA

Re: Assign a process to a processor

Bill McNAMARA_1 — Fri, 08 Jun 2001 12:15:18 GMT

This one is free.. instructions below

Later,
Bill

=======================================================================
Program to set processor affinity: (setproc.c)
-------------------------------------------------------------------------

#include
#include
#include
#include
#include

main(argc,argv)
int argc;
char *argv[];
{
gid_t sgid;
int i;
int pid;

if (argc < 2) {
printf("Usage: setproc spunum pid0 [pid1 ... pidn]\n");
exit(1);
}
sgid = atoi (argv[1]);
i = argc;
printf("Attempting to set process affinity for processor %d\n",
sgid);
while (i-- >2) {
pid = atoi(argv[i]);
if ((sgid = SETPROCESS(sgid, pid)) < 0)
perror("setprocess failed");
printf ("processor %d pid = %d\n", sgid, pid);
}
}
-------------------------------------------------------------------------

Compile the above program with

cc -o setproc setproc.c

The following shell script can be used to test that processor affinity
is working correctly:
--------------------------------------------------------------------
#!/bin/ksh

echo process id = $$
i=1

while [ "$i" -lt 10000 ]
do
echo " $i\r\c"
i=`expr $i + 1`
sleep 1
done
--------------------------------------------------------------------

You can start an instance of this script and use the setproc program on a
dual processor system to switch processes between processors. You should
run this on a seperate terminal since it will send the count to the
terminal every second.

You can then use the setproc program to move the process between
processors.

Usage:

setproc 0

to force to process to processor 0, or use

setproc 1

to force process to processor 1, etc.

Re: Assign a process to a processor

John Bolene — Fri, 08 Jun 2001 14:05:01 GMT

As Bill wisely said, you can dedicate a process to a processor, but you must have access to the source code and be able to compile it.

PRM is the only way that I know how to do it if you only have an executable binary file.

Re: Assign a process to a processor

Carsten Krege — Fri, 08 Jun 2001 15:32:38 GMT

With PRM you CANNOT force a process to run on a specific CPU. PRM can be used to ensure that a process (specifically a PRM group consisting of one ore more processes) cannot use more than a specific percentage of the total CPU resource (in times of high workload). The processes are not forced to run on a specific CPU though. THis would break many programs.

This can only be achieved with a program like Bill uses and which can force any PID to run on one specific CPU (ie you don't need the programs source), done by SETPROCESS which is a mpctl() system call.

Carsten

Re: Assign a process to a processor

John Bolene — Fri, 08 Jun 2001 18:14:51 GMT

Darn, every once in awhile you make a mistake.
Looks like this is my day.
I'll go to the doghouse for the rest of the day.