Re: [PATCH] ppc32 copy_to_user dcbt fixup

From: Bryan Rittmeyer
Date: Sat Mar 13 2004 - 02:49:55 EST

On Sat, Mar 13, 2004 at 03:50:03PM +1100, Benjamin Herrenschmidt wrote:
> It would be wise to make the dcbz as long as possible in "advance"
> before the actual write to the cache line.

I guess we could try "pre-dcbz" ala the dcbt prefetch code.
Even dcbz right before stw is probably cheaper than RAM
loading data that will be totally overwritten. It's hard to
lose eliminating bus I/O (especially reads).

Any comments on the dcbt prefetch patch?


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