> > 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.
