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Re: Quick question.

  • From: Alexei Roudnev
  • Date: Wed Aug 04 02:07:50 2004

>
> Alexei is talking about something else.
>
> > a duallie will keep the system up when a faulty process hogs 100%
> > CPU, because the second one is still available. That also increases
> > availability ratio.
>
> This is a resource problem, not an availibility problem. A spinning
> application is not going to take down the machine on any modern OS[2]
> and anyway can be dealt with with resource limits, SMP or not,
> presuming your OS supports resource limits.
In theory, yes. On pracrtice, 2 CPU improve behavior dramatically. 4 CPU
makes system too complex (as you wrote beloow).

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


>
> The real problem with SMP is kernel complexity. Drivers that are rock
s/is/was/ (5 years ago). Now most kernels are SMP. I agree that SMP kernels
are much more complicated, but we _already_ paid this price.

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.