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fatslob-:O said: Hmmm the black line does not directly connect to the cpu cache but rather if you look at the diagram it connects to a the bus of a cache which leads me to believe it exactly doesn't snoop the cpu's L1 and L2 cache but hUMA also requires things like volatile cache tag lines to mark what has changed from either sides of a cache so that a coherent cache bus can send the changes to either the cpu or gpu cache. |
Exactly... the difference between hUMA and NUMA is that the first you have the cache refresh in both (CPU and GPU) all the time (coherent)... in NUMA you need to refresh the cache before access the other memory (non-coherent), CPU need to update the CPU-cache to see all the latest GPU memory and GPU need to update the GPU-cache to see all the latest CPU memory.
