Western Digital's open sourced SweRV cores are approximately the same performance as the closed-source SiFive 7-series ones. The main difference is the WD core

Western Digital's open sourced SweRV cores are approximately the same performance as the closed-source SiFive 7-series ones. The main difference is the WD cores are 32 bit, no MMU, probably DTIM rather than cache (not sure). The guts of the dual issue decode, register file, pipeline is there, which is the hard part. The other bits could be relatively easily added by the open source community, probably cribbing components from RocketChip.