“How much NUMA architecture will the Bulldozer be, or in other words, if I have a 4-socket Bulldozer how much will memory access differ between access to memory local to the socket and access to memory from other CPUs in the box.“ – Mikael Ronström
With Non-Uniform Memory Access (NUMA) each processor has its own memory controller and its own memory banks (local access). Processors can also access memory from the other processors in the system (remote access.) NUMA enables this access.
In the past, in a 4P system, some memory locations were 2 hops away, leading to greater latency. In today’s current AMD Opteron™ 4000 and 6000 Series platforms, there are enough HyperTransport™ technology links that all of the remote memory calls are only one hop away.
There will be enhancements to our memory controllers, things we can’t talk about just yet, that we expect to help reduce the time to access memory, both locally and remotely.
HT Assist, a feature that was introduced with our six-core AMD OpteronTM processors, helps reduce memory traffic and speed up memory access from remote locations.
As for actual memory access timings, I will leave that for launch.