[PATCH][AArch64] Tune memcpy

Wilco Dijkstra Wilco.Dijkstra@arm.com
Fri Nov 6 14:41:00 GMT 2015


pinskia@gmail.com wrote:
> > def_fn memcpy p2align=6
> > +    prfm    PLDL1KEEP, [src]
> 
> Why keep rather than strm for the prefetches?

It improves small copies by prefetching the input immediately,  so setting
it to streaming would have an adverse effect as it claims the line will not
be used again. For huge copies the initial prefetch has no effect.

Wilco




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