W05.4.1 Hardware vs. Software Implementation of Warp-Level Features in Vortex RISC-V GPU

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Huanzhi Pu, Georgia Institute of Technology, United States

RISC-V GPUs present a promising path for supporting GPU applications. Traditionally, GPUs achieve high efficiency through the SPMD (Single Program Multiple Data) programming model. However, modern GPU programming increasingly relies on warp-level features, which diverge from the conventional SPMD paradigm. In this paper, we explore how RISC-V GPUs can support these warp-level features both through hardware implementation and via software-only approaches. Our evaluation shows that a hardware implementation achieves up to 4 times geomean IPC speedup in microbenchmarks, while softwarebased solutions provide a viable alternative for area-constrained scenarios.