On Tue, Nov 15, 2005 at 02:12:55PM +0100, Jens M Andreasen wrote: (good to see you're back on line :-)
> On a related subject: How is level one cache replaced with new data, > should one (or ones compiler) decide to use some of the prefetch > instructions available from Intel PII and up? It would make sense to > fetch the next dataset while doing what has to be done "now". On the > other hand, overwriting the current dataset is somewhat counter > productive. Unless you're hand-coding assembly it's probably wisest to leave this to the compiler. OTOH, I've no idea how smart gcc/g++ is in this respect. It could be quite interesting to -S some familiar DSP code and have a look at the result. The only place where I've seen prefetch used explicitly is in Brutefir's sse and 3dnow routines which I recently modified for use in one of my own projects. > The layout of the data would influence these decisions, no? And conversely, considerations relating to cache use (and possible sse optimisations) may influence your choice of data formats. -- FA
