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Re: Quick question.

  • From: Paul Jakma
  • Date: Wed Aug 04 02:51:06 2004

On Tue, 3 Aug 2004, Alexei Roudnev wrote:

In theory, yes. On pracrtice, 2 CPU improve behavior dramatically.
That is not about reliability. That's to do with software performance.

I was purely picking a, admittedly pedantic, nit with the notion that SMP == more reliable. I'm not trying to argue that SMP does not have other benefits (eg performance).

4 CPU makes system too complex (as you wrote beloow).
Nah, the big jump in complexity appears to be from no-concurrency to concurrency. After that initial hurdle, 2 to 4 to 8 CPUs isnt as big a deal (making it scale is though).

New P-IV with multi threading may be a good selection - behave as 2 CPU system but is not so complicated as SMP.

From the OS POV, the complication is the same. And yes, even
single-processors are today capable of presenting multiple execution contexts to software, and it seems to be a trend we'll see more and more of.

In reality, applications are less reliable on 2 CPU systems (if they have some kinds of bugs, which make sense on SMP only), so I agree with you in some cases.
Right..

regards,
--
Paul Jakma	[email protected]	[email protected]	Key ID: 64A2FF6A
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