Qs: 1->many Pentium CPU upgrade (kernel 2.2.5)

Igor Markov (imarkov@cs.ucla.edu)
Sun, 29 Aug 1999 18:26:02 -0700


Hello,

I have a few questions regarding the behavior of 2.2.5 and above
during a hardware upgrade. The answers that I would be most happy to
hear are "upgrade your hardware and everything will work just fine",
but I am not very optimistic (call it a hunch ;-). It seems important
to know the answers before buying new hardware, but I could not find
them in FAQs or other online docs. E.g., SMP is typically covered
either from the developer's point of view, while I mainly care about
not losing my system during upgrade and being able to run independent
processes on difft processors (e.g., using make -j2) afterwards.

If you believe my questions are not appriate for this list,
I'd be happy to receive suggestions as to better places to post at.
Pointers to relevant docs are also welcome.

Since I am not subscribed to this list,please
cc: imarkov@cs.ucla.edu
when replying

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I am running an out-of-the box (no kernel rebuilds/upgrades)
RedHat6.0 on a Pentium 150 w 96Mb RAM and a 3.2Gb HD.

The upgrade is motivated by two factors

o the latest gcc/g++2.95.1 (http://egcs.cygnus.com) can finally
compile my C++ code and I am not anymore confined to SunPro CC
or MSVC++
o our lab has a number of spare Pentium II/350 processors donated
from Intel and the multi-proc. motherboards do not look too much
pricier than uni-proc. ones.

I plan to buy a motherboard for 2 or 4 processors, a new case and new
memory (I've been told that my curr. 96Mb chips may not work well with
new boards). I am going to keep the peripherals.

The questions are

1. I expect the current [binary] kernel to recognize a new
motherboard and at least one new processor immediately after
the upgrade. Will that work if the board has 2 or 4 processors
installed?

2. One of the 2.2 kernel reviews on the Web alluded to
the possibility to turn SMP on w/o recompiling the kernel...
is this really possible or was that my misunderstanding ?

3. If I need to rebuild the kernel, I would also consider downloading
a newer one before rebuilding. Since I do not have problems with 2.2.5
running on one processor, I am curious if there are any advantages
in getting a new kernel. I do seem to have one of those Ethernet
cards that caused sudden death in combination w SMP, but I am not
using it since I have no Ethernet connection.

4. Any comments on choosing 2-processor vs 4-processor motherboard?
(Since I am going to use the processors for faster builds, it seems
I should be able to use 4 processors w no problem).

thanks,

Igor
P.S. Please cc: your replies to imarkov@cs.ucla.edu

-- 
  Igor Markov  office: (310) 206-0179   
  http://vlsicad.cs.ucla.edu/~imarkov

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