Hello,

I?m looking for a detailed document, including code sample, about
Cache Locking (locking instruction cache & data cache) in Intel
Pentium 4.

It should be similar to the documents I found below, which are for
XScale micro-architecture and CPU 80321.

http://www.intel.com/design/iio/papers/27387202.pdf
(look into section 4.5 and appendix C)

http://www.intel.com/design/intelxscale/27347302.pdf
(look into section 6.4 and its examples)


Thank you.
ARINTEL

---

Request for Question Clarification by pythagoras-ga on 29 Dec 2004 07:48 PST

Dear Sir

I have done a research.

I can give you 2 sites:
http://www.ift.ulaval.ca/~marchand/ift17584/Documentation/Optimizations.pdf
(look at chapter 6)

and for instructions (search on cache)
http://www.ift.ulaval.ca/~marchand/ift17584/Documentation/Instructions.pdf


If this is sufficient to you, I will post this as an offical answer.

Kind Regards

Pythagoras

---

Clarification of Question by arintel-ga on 29 Dec 2004 18:30 PST

Hello Pythagoras,

I have read through chapter 6 of Optimizations.pdf. I could not find
discussion of cache locking in there. It only discusses about
prefetch, which is different from cache locking.

In prefetch, "Prefetching too far ahead may cause eviction of cached
data from the caches prior to actually being used in execution; not
prefetching far enough ahead can reduce the ability to overlap memory
and execution latencies." (page 42)

Whereas, in cache locking, "when an application has a number of
important variables that are frequently accessed, it may improve
performance when those variables are locked into the cache. This keeps
them from being evicted when the cache becomes full, resulting in
fewer accesses to main memory."
(http://www.intel.com/design/iio/papers/27387202.pdf, page 11)

Chapter 6 in Optimizations.pdf also discusses cache blocking. However,
as I understand it, cache blocking is just a technique that uses
prefetch to deal with one- or two-dimensional arrays, which is, again,
not cache locking.

Regarding the document Instructions.pdf, I'm sorry I don't understand
its language. Do you have its english version?

Thanks a lot for your replies.
Regards,
ARINTEL