Re: Pentium SSE prefetcht0 instruction... How do you make it work

[Bulent Abali]

>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.
>
>--Tony
PREFETCHx are in P3. I am aware that processor executes them optionally.
MFENCE may be a good idea.  If load/store queues are full the processor
may just drop the prefetch instruction.  I should try this.
Thanks for the suggestion.  /bulent