Checksum/copy

[Dag-ErlingSmørgrav]

David Malone <dwmalone at maths.tcd.ie> writes:
> On Thu, Mar 27, 2003 at 09:57:35AM +0100, des at ofug.org wrote:
> > Might it be a good idea to have separate b{copy,zero} implementations
> > for special purposes like pmap_{copy,zero}_page?
> We do have a i686_pagezero already, which seems to be used in
> pmap_zero_page - I guess it may not be well tuned to modern processors,
> as it is almost 5 years old.

i686_pagezero uses 'rep stosl' after an initial 'rep scasl' to check
if the page was already zero (which is a pessimization unless we zero
a lot of pages that are already zeroed).  SSE can do far better than
that.

DES
-- 
Dag-Erling Smørgrav - des at ofug.org