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This paper describes the methods and simulation techniques used to verify the functional correctness and performance attributes of the IBM POWER5TM microprocessor and the eServerTM p5 systems based on it. The approaches used were based on migrating the best practices that had been used to verify the POWER4TM chip. The POWER5 chip design posed new challenges to the simulation team with the addition of simultaneous multithreading (SMT) and dynamic power management (DPM). In addition, there was further integration of cache and memory subsystem function onto the POWER5 chip. Since the design complexity had increased from the POWER4 design, the use of test plan coverage tools and techniques was expanded to ensure the maximum effectiveness of each simulation cycle run. A new toolset was also employed to improve the utilization of the large pool of computers used to run batch simulation jobs and to provide more efficient fail reproduction and bug fix management. For the system-level verification, a new test-case-generation tool was utilized which allowed for more targeted testing through a deeper knowledge of the system topology. In parallel with the mainline functional validation, verification of reliability functions and performance attributes also had increased focus for the POWER5 design.

This paper describes the methods and simulation techniques used to verify the microarchitecture design and functional performance of the IBM POWER4 processor and the POWER4-based Regatta system. The approach was hierarchical, based on but considerably expanding the practice used for verification of the CMOS-based IBM S/390 Parallel Enterprise Server™ G4. For POWER4, verification began at the abstract, high-level design phase and continued throughout the designer and unit levels, the multi-unit level, and finally the multiple-chip system level. The abstract (high-level design) phase permitted early validation of the POWER4 processor design prior to its commitment to HDL. The designer and unit-level stages focused on ensuring the correctness of the microarchitectural components. Multiunitlevel verification, performed on storage and I/O components as well as on the processor, confirmed architectural compliance for each of the chips and subsystems. Finally, systemlevel verification tested multiprocessor coherence and system-level function, including processor-to-I/O communication and validation of multiple hardware configurations. In parallel with design and functional validation, verification of reliability functions, performance, and degraded configurations was also performed at most of the levels in the hierarchy.