Do multi-core CPUs share the MMU and page tables?

Question

On a single core computer, one thread is executing at a time. On each context switch the scheduler checks if the new thread to schedule is in the same process than the previ

Answer 1

On the question of MMUs per processor there may be several. The assumption is that each MMU will add additional memory bandwidth. If DDR3-12800 memory allows 1600 mega-transfers per second on a processor with one MMU then one with four will theoretically allow 6400. Securing the bandwidth to the cores available is probably quite a feat. The bandwidth advertised will be whittled away quite a bit in the process.

The number of MMUs on a processor is independent of the number of cores on it. The obvious examples are the 16 core CPUs from AMD, they definitely don't have 16 MMUs. A dual-core processor, on the other hand, might have two MMUs. Or just one. Or three?

Edit

Maybe I'm confusing MMUs with channels?