Non-Intrusive Scalable Memory Access Tracer

Memory access tracing is one of the widely used methods to evaluate, analyze, and optimize hardware and software designs. We are developing a non-intrusive, scalable, full-address-range memory tracer. The tracer hardware board is compliant with the JEDEC DDR3 DIMM form factor, and fits in a DIMM slot. It is so compact that we can populate up to 16 tracer boards in a 4-CPU server chassis, and record the commands and addresses of all the memory accesses. Each board drives four SSDs to record the memory access addresses without a break until the SSDs are full. For example, we can make a trace of a full SPECjbb 2005 run, which lasts 26 minutes and generates over 11TB trace data. In addition to recording memory accesses, it collects various types of statistical data, such as a large number of segmented read/write statistics and DRAM bank utilization rates, and displays them on the control dashboard in real time.