Re: Pentium SSE prefetcht0 instruction... How do you make it work
Robert Love (rml@ufl.edu)
27 Sep 2001 15:55:35 -0400
On Thu, 2001-09-27 at 14:43, Tony Hagale wrote:
> Intel's p3/4 prefetch instructions are hints only. They are only executed
> asynchronously, and depend heavily on the other load on the processor at
> the time. They are not required to prefetch, *and* they are not required
> to be executed when you think they should in the flow of the program. You
> can serialize them by using an MFENCE instruction, but they still aren't
> guaranteed to run.
>
> Check the p4 manuals. In fact, I'm not sure prefetch was implemented in
> p3. I could be wrong, check the manual.
prefetch is in P3 and P4.
there are prefetcht0, prefetcht1, prefetcht2, and prefetchnta
instructions, Intel's programming docs have references on these all
online.
--
Robert M. Love
rml at ufl.edu
rml at tech9.net
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