The Memory stress (Mess) framework provides a unified view of the memory system benchmarking, simulation and application profiling. The Mess benchmark provides a holistic and detailed memory system characterization. It is based on hundreds of measurements that are represented as a family of bandwidth-latency curves. The benchmark increases the coverage of all the previous tools and leads to new findings in the behavior of the actual and simulated memory systems. We deploy the Mess benchmark to characterize Intel, AMD, IBM, Fujitsu, Amazon and NVIDIA servers with DDR4, DDR5, HBM2 and HBM2E memory. The Mess memory simulator uses bandwidth-latency concept for the memory performance simulation. We integrate Mess with widely-used CPUs simulators enabling modeling of all high-end memory technologies. The Mess simulator is fast, easy to integrate and it closely matches the actual system performance. By design, it enables a quick adoption of new memory technologies in hardware simulators. Finally, the Mess application profiling positions the application in the bandwidth-latency space of the target memory system. This information can be correlated with other application runtime activities and the source code, leading to a better overall understanding of the application's behavior. The current Mess benchmark release covers all major CPU and GPU ISAs, x86, ARM, Power, RISC-V, and NVIDIA's PTX. We also release as open source the ZSim, gem5 and OpenPiton Metro-MPI integrated with the Mess simulator for DDR4, DDR5, Optane, HBM2, HBM2E and CXL memory expanders. The Mess application profiling is already integrated into a suite of production HPC performance analysis tools.

We propose the Active Compute Memory (ACM), a near-memory-processing architecture capable of performing key–value sort directly in the DRAM. In the ACM architecture, sort is merely the writing of data into memory with one addressing protocol (perspective) and reading it back with different perspective. The first perspective is conventional, based on the data address; the second perspective is the sorted order. The ACM requires additional tables to store the meta-data and moderate control logic enhancements that can be implemented directly in the DRAM silicon. By these modest enhancements to DRAM, ACM exploits the parallelism inherently available in the row buffer to enable sort with$O(n)$complexity. This leads to an order of magnitude improvement in ACM performance and energy compared to conventional$O(n\log{}n)$CPU-centric sort algorithms. The ACM also shows superior performance compared to other near-memory sort accelerators. This is because the ACM processing is done near the row buffer and it exploits much lower memory access latency, higher bandwidth and wider parallel processing. The sort operation covered in this paper is just an example of an address management operation that can be efficiently implemented directly in the DRAM silicon. We release as an open source the simulation infrastructure for the ACM performance and energy modeling. We would encourage the community to use it, adapt it to other PIM proposals, and share their own evaluations.