On Tue, Jul 02, 2013 at 12:07:10PM +0100, Chris Wilson wrote: > On Tue, Jul 02, 2013 at 01:58:13PM +0300, Ville Syrj?l? wrote: > > Also IIRC someone told me that w/ uncached mappings the caches aren't > > snooped even on LLC platforms. If that's true, MOCS seems even more > > dangerous since the client could easily mix cached and uncached > > accesses. I don't really understand why uncached mappings wouldn't > > snoop on LLC platforms since the snooping should be more or less free. > > Who said that? Doesn't appear to be the case on SNB/IVB/HSW as far as I > can tell. Can't remember now who said it, or could be I just misunderstood. But if it's not true, then MOCS seems actually useful. Otherwise it's going to be a clflush fest when you want to change from cached to uncached. -- Ville Syrj?l? Intel OTC
