topic Re: disable one Processor in Operating System - HP-UX

disable one Processor

SupraTeam_1 — Mon, 17 Oct 2005 07:42:28 GMT

Hello all,
I would like to disbale one processor in my work station C8000 just for a test.
And to enable the two processors at the end of my test.
How can i do that ?

This is my work station :

System Hardware

Model: 9000/785/C8000
Main Memory: 8190 MB
Graphics: ATI Fire GL X3 color 0x0 48 planes
Processors: 2
OS mode: 64 bit
LAN hardware ID: 0x00110A31AB53
Software ID: Z56bc8c4b0d22834d
Keyboard Language: USB_PS2_DIN_US_English

Thanks

Re: disable one Processor

Arunvijai_4 — Mon, 17 Oct 2005 07:58:25 GMT

A similar thread worth reading,

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=133209

1. Reboot the machine
2. Interrupt the boot by pressing any key within the 10 second window
3. Type CO - to enter configuration mode
4. Type CPU - to determine which CPU to turn off
5. Type CPU OFF - to turn off CPU
6. Type RESET - to reboot the machine, for the changes to take affect.

-Arun

Re: disable one Processor

Jeff Schussele — Mon, 17 Oct 2005 07:58:38 GMT

HI,

You need to reboot the system & interrupt the boot.
At the BCH> prompt type CO for configure.
Then CPU will show current state.
Then CPU 1 off to disable the 2nd processor.
CPU again shows current state & should show that #1 is marked to be deconfigured
Then MA to get back to main menu.
Then RS to reset the system. You must do this or it will boot up with both active still.
Just repeat this using CPU 1 on to reconfigure it back active.

HTH,

Re: disable one Processor

SupraTeam_1 — Mon, 17 Oct 2005 08:09:29 GMT

If i disable the 1 or 0, i have an error :
cnnot deconfigure the last processor

Re: disable one Processor

Jeff Schussele — Mon, 17 Oct 2005 08:15:50 GMT

What does the CPU command alone return?
Is it possible that 1 is already deconfigured?
May be bad & was auto-deconfigured.

Rgds,
Jeff

Re: disable one Processor

Arunvijai_4 — Mon, 17 Oct 2005 08:18:22 GMT

Just check this link,

http://safariexamples.informit.com/0131018833/Firmware/Hardware.txt

-Arun

Re: disable one Processor

Denver Osborn — Mon, 17 Oct 2005 08:20:04 GMT

I'd have to look up the specs for that box. if it's a dual core processor, I don't think you'd be able to disable the a dual core cpu to act as a single cpu.

-denver

Re: disable one Processor

SupraTeam_1 — Mon, 17 Oct 2005 08:23:12 GMT

I think it's a dual core, it's possible to do what ia want ?

P.S.: i see my 2 cpu in CO and they are configured

Re: disable one Processor

Denver Osborn — Mon, 17 Oct 2005 08:24:06 GMT

ok, found it... C8000 has a PA8800 or PA8900 dual core processor. two cpu slots so it could perform as a 2 or 4 way w/ only 1 or 2 dual processors installed.

http://www.hp.com/workstations/risc/c8000/c8000.pdf

So I guess the next question would be... is it possible to "disable" 1/2 of a dual core processor? :) I doubt it, but I can't speak from experience.

Hope this helps,
-denver

Re: disable one Processor

Jeff Schussele — Mon, 17 Oct 2005 08:33:07 GMT

Hi,

I think Denver has hit it.
IF it's a dual-core you cannot disable any part of it. Can only disable the whole CPU AFAIK.

Rgds,
Jeff

Re: disable one Processor

SupraTeam_1 — Mon, 17 Oct 2005 08:34:11 GMT

And have you got an idea, in order to affect all process on one core ?

Re: disable one Processor

Arunvijai_4 — Mon, 17 Oct 2005 08:38:34 GMT

Just check with your system BIOS(if any) for enabling/disabling dual core .. Just a thought , i never done this...

-Arun

Re: disable one Processor

SupraTeam_1 — Mon, 17 Oct 2005 09:47:41 GMT

Thans fot ALL... No solution :o(

Re: disable one Processor

rick jones — Tue, 18 Oct 2005 11:23:15 GMT

While you are not premitted to disable the second core of a dual-core CPU from firmware, you can effectively disable it after the OS has booted. You would use intctl to move all I/O card interrupts off the CPU you wish to "disable," and then use processor sets to prevent anything from being scheduled on that CPU. The CPU is still "alive" and sitting in the kernel idle loop, but it should not be contributing to any useful work :)

I'm not sure if the HP-UX kernel has a way to be told to boot as if the system is UP. That may be another way to go.