Summay: dual processor on Sparc20

From: Janet Leung (
Date: Fri Mar 20 1998 - 17:17:55 CST

Thanks to:
Brion Leary <>
Kelly Fergason <>
Casper Dik <casper@holland.Sun.COM>
"C. Allen" <>
Peter Bestel <>
Benjamin Cline <>
Jay Lessert <>
"Angell, Harold R" <>
"David J. Knight" <>
Jeff Woolsey <>
David Thorburn-Gundlach <>
"Marks, Evan" <>
Matthew Stier <>
"Marc S. Gibian" <>
"Christopher L. Barnard" <>
Sean Ward <>
Chad Smith <>
"Michael J. Connolly" <>

Consensus: Nothing is required of the admin for the second processor.
Not even the boot -r.

More detailed answers to Q #1
- I don't think you even need to do a 'boot -r' ; it can't hurt
- Although I'd recommend for performance reasons that you use at least
  2.5.1, rather than 2.5. 2.6 requires more looking into what
  apps/kernel dependencies you have.
- No problems as far as the hardware is concerned. As for software, I
  would query any 3rd party software vendors before installing it/them.
  No problems with SUN software (compilers, Solstice Backup, VM,
  Disksuite, ...).
- Double the RAM at the same time since both processors will share the
  same RAM
- Can use the psradm command to online and offline processors at will!
- You do not need to type "boot -r" command, this may cause problems if
  your kernel has special configuration and "boot -r" will over write
  it, and this may cause problems.

Answers to Q #2: no.
Related feedback
The only applications affected by multiprocessor systems, are those that
try to report system statistics. They were designed in the single
processor era, and often do not accurately report statistics for
multiprocessor systems.
Certain kernel-intensive applications like top and lsof will probably
work, but they may not give you any information about the extra
processors. You will have to recompile those to get the maximum benefit.
You'll have to contact manufacturer's tech support for these applications
to see if it was designed for multiprocessor environment. If a application
was written for a single processor environment, it should still work, but
it'll only use one processor.

Original question
We have a Sparc20 running Solaris 2.5, and we are thinking about adding
another processor to it. We would like to know if you guys have
installed extra processors before or not, and whether you have run into
any major problems. Some of our concerns are as follows:

1. Do we need to re-install the OS in order to take advantage of the dual
   processors, or a normal "boot -r" will do the job?

2. Will there be any applications that might not work on a dual-processor

Your feedback and input is greatly appreciated.

Janet Leung, TACTech, Inc., Yorba Linda, CA 92887-4608

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