Genuine question since you seem to care about the performance:

As an outsider, where we are with GPUs looks a lot like where we were with CPUs many years ago. And (AFAIK), the solution there was three-part compilers where optimizations happen on a middle layer and the third layer transforms the optimized code to run directly on the hardware. A major upside is that the compilers get smarter over time because the abstractions are more evergreen than the hardware targets.

Is that sort of thing possible for GPUs? Or is there too much diversity in GPUs to make it feasible/economical? Or is that obviously where we're going and we just don't have it working yet?

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nicoburns 6 days ago | parent [-]

The status quo in GPU-land seems to be that the compiler lives in the GPU driver and is largely opaque to everyone other than the OS/GPU vendors. Sometimes there is an additional layer of compiler in user land that compilers into the language that the driver-compiler understands.

I think a lot of people would love to move to the CPU model where the actual hardware instructions are documented and relatively stable between different GPUs. But that's impossible to do unless the GPU vendors commit to it.

	▲	pornel 6 days ago \| parent \| next [-]
		I would like CPUs to move to the GPU model, because in the CPU land adoption of wider SIMD instructions (without manual dispatch/multiversioning faff) takes over a decade, while in the GPU land it's a driver update. To be clear, I'm talking about the PTX -> SASS compilation (which is something like LLVM bitcode to x86-64 microcode compilation). The fragmented and messy high-level shader language compilers are a different thing, in the higher abstraction layers.
	▲	sim7c00 6 days ago \| parent \| prev [-]
		i think intel and amd provide ISA docs for their hw. not sure about nvidia didnt check it in forever