If you bypass the L2 cache, it's pointless because the next
agent (PCI controller, CPU thread, etc.) is going to need the
data in the L2 cache.

It's better in that kind of setup to eat the L2 cache miss overhead in
memcpy since memcpy can usually prefetch and store buffer in order to
absorb some of the L2 miss costs.

I thought that most PCI controllers (that is to say the things bridging 
PCI to the rest of the system) could do prefetching and/or that PCI-X 
(if not PCI, no idea about PCI-e) cards could issue multiple 
transactions anyway?

rick jones