Re: [discuss] Re: FOR REVIEW: New x86-64 vsyscall vgetcpu()

From: Andi Kleen
Date: Mon Jun 19 2006 - 04:53:19 EST



> Probably I have not explained it correctly:
> - The "information page" (that includes the current CPU no.) is not a
> per CPU page

If it isn't then you can't figure out the current CPU/node for a thread.

Anyways I think we're talking past each other. Your approach might
even work on ia64 (at least if you're willing to add a lot of cost
to the context switch). You presumably could implement vgetcpu()
internally with an approach like this (although with IA64's fast
EPC calls it seems a bit pointless)

It just won't work on x86.

-Andi
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