So here's what I would do if I were in this situation. I wouldn't build a graphics processing unit per se, but instead would build a highly parallel SIMD CPU organized in workgroups, and with workgroup-local shared memory. These cores could be relatively simple in some respects (they wouldn't need complex out-of-order superscalar pipelines or sophisticated branch prediction), but should have good simultaneous multithreading to hide latency effectively.

Then, if you wanted to run a traditional rasterization pipeline, you'd do it basically in software, using approaches similar to cudaraster (which is BSD licensed!). The paper on that suggests that it would be on the order 2X slower than optimized GPU hardware for triangle-centric workloads, but that might be worth it. The good news is this story gets better the more the workload diverges from what traditional GPUs are tuned for - in particular, the more sophisticated the shaders get, the more performance depends on the ability to just evaluate the shader code efficiently.

It would of course be very difficult to make a chip that is competitive with modern GPUs (the engineering involved is impressive by any standards), but I think a lot would be gained from such an effort.

I should probably disclaim that this is definitely not legal advice. Anyone who wants to actually play in the GPU space should plan on spending some quality time with a team of topnotch lawyers.

(project author here) That is pretty close to the approach this project has taken, although my motivation was not so much avoiding IP as exploring the line between hardware acceleration and software.

allo jeff nice to see you're around :) thank you so much for the time you spend guiding me through nyuzi. also for explaining the value of the metric "pixels / clock" as a measure for iteratively being able to focus on the highest bang-per-buck areas to make incremental improvements, progressing from full-software to high-performance 3D.

have you seen Tom Forsyth's fascinating and funny talk about how Larrabee turned into AVX512 after 15 years?

https://player.vimeo.com/video/450406346 https://news.ycombinator.com/item?id=15993848

Great to hear! I've poked around a little and see that, and in any case wish you success and that we can all learn from it.

To clarify further, Nvidia and AMD (and probably other small players like ARM, Quallcomm, Imagination) own the patents on core shader tech, which are the building blocks of any modern GPU design.

If you want to design a GPU IP that works around all their patents, you probably can, but unless you're a John Carmack x10, your resulting design would be horribly inefficient and not competitive enough to be worth the expensive silicon it will be etched on and probably not compatible to any modern API like Vulcan or DirectX.

But if you just want to build your own meme GPU for education/shits and giggles, that doesn't follow any patents or APIs, then you can and some people already did:

https://www.youtube.com/watch?v=l7rce6IQDWs

I am not in the graphics space but I am quite familiar with tech business practices.

I think the chance you would be sued is near 100%. If you released and showed any market traction at all, you would immediately become a threat to the duopoly; they surely remember the rise of 3Dfx. Don’t bother arguing the merits of the patents because it would be a business decision, not a technical one—this is the kind of thing that’s decided at the C-level and then justified (or cautioned against) by the company’s legal team, not the other way around. Patents are merely leverage to effect the defense of the business, and you can be sure they’ll be used.

I agree with you (and definitely a conversation worth having) but for the sake of this thread let’s pretend that legal action would only be taken when a patent was actually matched with what was put in the chip.

I’m sad you’re being downvoted because I would also have been interested in the discussion, but I think the unfortunate reality is it just doesn’t matter that much.

I appreciate voicing that you’d also be interested in that discussion. These days it feels to me as though patents and litigation are such a large battleground that they dwarf conversations like these, but underneath it all patents do still exist the way they used to and that seems to me like that still means that these discussions are important.

if it were done, say, as a Libre/Open processor, say, with the backing of NLnet (a Charitable Foundation), where the "Bad PR ju-ju" for trying it on was simply not worth the effort

if it were done. say, as a Libre/Open processor, say, with the backing of NLnet (a Charitable Foundation), where NLnet has access to over 450 Law Professors more than willing to protect "Libre/Open" projects from patent trolls by running crowd-funded patent-busting efforts

if it were done as a Libre/Open Hybrid Processor, based on extending an ISA such as ooo, I dunno, maybe OpenPOWER, which has the backing of IBM with a patent portfolio spanning several decades, who would be very upset if tiny companies like NVidia or AMD tried it on against a Charitably-funded project.

that would be a very interesting situation, wouldn't it? i wonder if there's a project around that's trying this as a strategy? hmmm, hey, you know what? there is! it's called http://libre-soc.org