Re: x86: Is there still value in having a special tlb flush IPI vector?

From: Jeremy Fitzhardinge
Date: Mon Jul 28 2008 - 19:21:14 EST


Resend to cc: Andi on an address which actually works.

Jeremy Fitzhardinge wrote:
Now that normal smp_function_call is no longer an enormous bottleneck, is there still value in having a specialised IPI vector for tlb flushes? It seems like quite a lot of duplicate code.

The 64-bit tlb flush multiplexes the various cpus across 8 vectors to increase scalability. If this is a big issue, then the smp function call code can (and should) do the same thing. (Though looking at it more closely, the way the code uses the 8 vectors is actually a less general way of doing what smp_call_function is doing anyway.)

Thoughts?

(And uv should definitely be hooking pvops if it wants its own flush_tlb_others; vsmp sets the precedent for a subarch-like use of pvops.)

J
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