Messages in this thread | | | Date | Sat, 16 Aug 2008 21:25:37 +0100 (BST) | From | "Maciej W. Rozycki" <> | Subject | Re: [PATCH 2/6] x86: apic - unify lapic_resume |
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On Sat, 16 Aug 2008, Arjan van de Ven wrote:
> it's not like you can/want to go over 128 cpus on a 32 bit kernel > though..
That's a quantitative rather than a qualitative limitation though. I can see no reason why limiting the number of CPUs would preclude the use of the x2APIC mode altogether -- the extra CPUs will simply be ignored and never waken up. And with smaller systems and a 32-bit kernel one may still want to get the small performance gain from using the MSRs rather than going through the TLB for example.
Similarly there is some RAM size limitation with the 32-bit configuration too, but that does not prevent us from using however much we can in the 32-bit mode either. ;)
Maciej
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