>There's another effect here which might get overlooked - and which appears to >vary between Intel and AMD systems. Intel multicore processors seem to have >L1 cache dedicated to individual processors but share L2 between them. On the >contrary, AMD multicore processor caches seem to be dedicated at both L1 and >L2, the sharing is done in the memory controller. > >
two CPU cores sharing a common L2 cache don't have to send 'cache snoop' cycles and other coherency overhead over the bus, in a seperate cache-per-CPU system, these snoop cycles can use quite a lot of time when you have frequent cache misses (and even worse, when both CPUs are frequently writing to the same location for interprocess communications or whatever, that row has to be repeatedly flushed from each cache). _______________________________________________ Prime mailing list [email protected] http://hogranch.com/mailman/listinfo/prime
