Evaluation of NUMA memory management through modeling and measurements

Dynamic page placement policies for NUMA (nonuniform memory access time) shared-memory architectures are explored using two approaches that complement each other in important ways. The authors measure the performance of parallel programs running on the experimental DUnX operating system kernel for the BBN GP1000, which supports a highly parameterized dynamic page placement policy. They also develop and apply an analytic model of memory system performance of a local/remote NUMA architecture based on approximate mean-value analysis techniques. The model is validated against experimental data obtained with DUnX while running a synthetic workload. The results of this validation show that, in general, model predictions are quite good. Experiments investigating the effectiveness of dynamic page-placement and, in particular, dynamic multiple-copy page placement the cost of replication/coherency fault errors, and the cost of errors in deciding whether a page should move or be remotely referenced are described