On Fri, Apr 21, 2006 at 07:06:13AM +1000, Benjamin Herrenschmidt wrote: > (On 6xx this is deadly even if you don't access those cacheable pages > because the CPU prefetch may do it for you).
Here is another thought if this "prefetch" theory is correct. You guys seems to focus on dma_alloc_coherent()/pci_alloc_consistent(), but forgeting about so called "streaming" mappings. You cannot just flush/invalidate cache any more, because "CPU can prefetch this data back". So, to be completely correct (if you insist on "6xx can prefetch"-theory), you have to actually _copy_ data to your consistent memory on dma_map_single(). You can imagine performance implications. I suspect even 440 will be faster in this case than G4 :). -- Eugene -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
