Re: Page fault scalability patch V18: Drop first acquisition of ptl

[David S. Miller]

On Thu, 03 Mar 2005 17:30:28 +1100
Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote:

> On Fri, 2005-03-04 at 04:19 +1100, Nick Piggin wrote:
> 
> > You don't want to do that for all architectures, as I said earlier.
> > eg. i386 can concurrently set the dirty bit with the MMU (which won't
> > honour the lock).
> > 
> > So you then need an atomic lock, atomic pte operations, and atomic
> > unlock where previously you had only the atomic pte operation. This is
> > disastrous for performance.
> 
> Of course, but I was answering to David about sparc64 which uses
> software TLB load :)

Right.

The current situation on sparc64 is that the tlb miss handler is
~10 cycles.

Like I said, I can use this thing if it just increases access, without
modifying the TLB miss handler at all.

Hmmm... let me think about this some more.
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