Re: [RFC] x86-64: Use SSE for copy_page and clear_page

[michael]

Andi Kleen <ak@xxxxxx> writes:

> > Thus with "normal" page clear and "nt" page copy routines
> > both clear and copy benchmarks run faster than with
> > stock kernel, both with small and large working set.
> > 
> > Am I wrong?
> 
> fork is only a corner case. The main case is a process allocating
> memory using brk/mmap and then using it.

Key point: "using it". This normally involves writes to memory. Most
applications don't commonly read memory that they haven't previously
written to. (valgrind et al call that behaviour a "bug" :).

Given that, I'd say you really don't want the page zero routines
touching the cache.

Michael.
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