ZSim

ZSim is a cycle-accurate full-system simulator used in computer architecture research to model modern multiprocessor systems, including CPUs, memory hierarchies, and I/O subsystems. It emphasizes scalability and the ability to evaluate architectural ideas without fabricating hardware.

The simulator employs a modular, event-driven architecture that can model multicore processors with detailed cache hierarchies, coherence protocols, memory controllers, and interconnects. It can run operating systems such as Linux and execute real workloads alongside synthetic benchmarks, and supports both detailed, cycle-accurate execution and faster, approximate modes.

ZSim originated in academic research environments and has been maintained by a community of researchers and contributors since its inception, with multiple releases and ongoing updates to support modern architectures and workloads.

Common applications include evaluating cache design and memory systems, exploring new coherence schemes, studying memory-level parallelism, and comparing architectural trade-offs. It is frequently used in university labs and industrial research projects alongside other simulators.

The project is distributed to researchers via downloadable source code and documentation; users typically build and run simulations on standard Linux systems, sometimes leveraging parallel hardware to improve simulation throughput. It is often discussed in connection with other architectural simulators such as Gem5 and other full-system tools.