Re: [PATCH 11 of 11] x86: defer cr3 reload when doing pud_clear()

[H. Peter Anvin]

Andi Kleen wrote:
> > so INVLPG makes sense for pagetable fault realated single-address 
> > flushes, but they rarely make sense for range flushes. (and that's how 
> > Linux uses it)
>
> I think it would be an interesting experiment to switch flush_tlb_range()
> over to INVLPG if the length is below some threshold and see if there 
> are visible effects in macro benchmarks. The main problem
> would be to determine the right threshold -- would likely be CPU dependent.

It would be an interesting experiment.  Odds are pretty good that the 
cutover is roughly linear in the TLB size.

	-hpa
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