ArchExplorer: Microarchitecture Exploration Via Bottleneck Analysis

Design space exploration (DSE) for microarchitecture parameters is an essential stage in microprocessor design to explore the trade-offs among performance, power, and area (PPA). Prior work either employs excessive expert efforts to guide microarchitecture parameter tuning or demands high computing resources to prepare datasets and train black-box prediction models for DSE.

In this work, we aim to circumvent the domain knowledge requirements through automated bottleneck analysis and propose ArchExplorer, which reveals microarchitecture bottlenecks to guide DSE with much fewer simulations. ArchExplorer consists of a new graph formulation of microexecution, an optimal critical path construction algorithm, and hardware resource reassignment strategies. Specifically, the critical path is constructed from the microexecution to uncover the performance-critical microarchitecture bottlenecks, which facilitates ArchExplorer to reclaim the hardware budgets of performance-insensitive structures that consume unnecessary power and area. These budgets are then reassigned to the microarchitecture bottlenecks for performance boost while maintaining the power and area constraints under the total budget envelope. Experiments show that ArchExplorer can find better PPA Pareto-optimal designs, achieving an average of 6.80% higher Pareto hypervolume using at most 74.63% fewer simulations compared to the state-ofthe-art approaches.

• This work is done during Chen Bai's internship at Alibaba DAMO Academy. † Part of the work was done while the author was with Alibaba DAMO Academy.