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> In the end I think including the high level compilers and APIs in the proprietary driver stack responsibility is unsustainable. Microsoft seems to have a bett

by paulmd 3y ago

> In the end I think including the high level compilers and APIs in the proprietary driver stack responsibility is unsustainable. Microsoft seems to have a better model, or there could be even a standard JIT code consumed by drivers that emitted by open source stacks shared across platforms. The latter way would also better support development of nicer GPU languages. OK, let's talk MS. What NVIDIA has done with PTX is basically the same thing as MSIL/CIL. There is a meta-ISA/meta-language that has been commonly agreed, and if you invoke no tokens that the receiving driver doesn't understand, the legacy compiler understands and emits executable (perhaps not optimal) code. The legacy hardware stays on a specific driver and a specific CUDA support level. The CUDA support level is everything, that is your entire "feature profile". It's not GFX1030/GFX1031, it's RDNA3.0/3.1/whatever. NVIDIA has been able to maintain their feature support (not implementation details) in a monotonically increasing sequence. Additionally, they also maintain a guarantee that spec 3.1 guarantees that you can also compile and execute 3.0 code. "Upwards family correctness" I guess. Again, doesn't have to be optimal but the contract is there's no tokens that you don't understand. A Tegra 7.0 compiler can compile desktop 7.0 CUDA (byte/)code etc. https://en.wikipedia.org/wiki/CUDA#Version_features_and_specifications https://en.wikipedia.org/wiki/CUDA#Version_features_and_spec... Legacy driver support doesn't change, so, you can always read PTX, you can always read anything that's compiled for your CUDA Capability Level even if it's from a future toolkit that wasn't released at the time. PTX is always the ultimate "emit code from 2020 and run on the 2007 gpu that only understands CUDA 1.3" relief valve though. If you don't write code that does stuff that's illegal in 1.3... it'll compile and emit PTX, and the Tesla driver will parse and run it. Anyway, let's talk MS. MS could come up with MSIL/CIL. NVIDIA can come up with PTX. Why can't AMD do this? What is unique about GCN/RDNA as a language that you can't come up with an intermediate language representation?

fulafel 3y ago
I agree that AMD could have done a proprietary intermediate instruction format and with good execution it would have made their users lives easier. But the actual big opportunity which could make the whole GPU programming field far more dev friendly and could make the gpu vendor competition work in favour of users would be doing the GPU-IL in a cross-vendor way, driven by someone else than a single GPU vendor who is playing in the proprietary lock-in game (or certain to do it after gaining sufficient market position).

by paulmd 3y ago

fulafel 3y ago

I agree that AMD could have done a proprietary intermediate instruction format and with good execution it would have made their users lives easier. But the actual big opportunity which could make the whole GPU programming field far more dev friendly and could make the gpu vendor competition work in favour of users would be doing the GPU-IL in a cross-vendor way, driven by someone else than a single GPU vendor who is playing in the proprietary lock-in game (or certain to do it after gaining sufficient market position).