More Details On The Proposed Simple-V Extension To RISC-V For GPU Workloads

With the proposed Libre RISC-V Vulkan accelerator aiming to effectively be an open-source GPU built atop the open-source RISC-V ISA there were recently some new details published on how the design is expected to work out.

For this very ambitious libre RISC-V SoC design. that EOMA68 developer Luke Kenneth Casson Leighton wants to pursue through crowdfunding, it's just not a matter of spinning his own RISC-V design but for making the SoC suitable for GPU workloads he has talked of a "Simple-V" extension he envisions.

Over the holidays he shed more light on this Simple-V extension he wants to develop for RISC-V that he thinks could make it more suitable for GPU performance. Keep in mind, it's looking like this hypothetical SoC will just be around a 64-bit quad-core 800MHz part.

Simple-V in effect is: "mark ordinary registers as “vectorised,” and when an instruction uses one such “tagged” register, go into a hardware-unrolled version of a software macro loop, issuing otherwise identical instructions with contiguous sequentially-increasing register numbers."

But even with Simple-V, the initial performance target for this SoC/GPU should it reach production is 25 FPS @ 720p and around 5~6 GFLOPs compute power.

For those wishing to learn more about the planned very low-level, technical details of Simple-V can do so via this blog post.

L.K.C.L. also commented that he is pursuing an "ethical" design to the GPU/SoC:

The project is being run along ethical lines. That in particular means unanimous decision-making. Nobody gets to over-rule anyone else: everyone matters, and everyone’s input matters. So if I think Tomasulo is better, it’s up to me to keep on researching and evaluating and reasoning until I have convinced everyone else… or they have convinced me otherwise.

I have it on good authority from some extremely comprehensive research that this is a hell of a lot better way to do decision-making than “mob-rule” voting. “Mob-rule” voting (a.k.a. “democracy”) basically automatically destroys the morale and discounts the will of the “minority.” No wonder democratic countries have minority representation political groups, because it’s heavily brainwash-ingrained into people living in such countries that the minority view shall be disregarded; of course they feel the need to shout and get angry!