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I really hope they open source their compiler and allow people to program directly to the machine code. Part of the problem with GPUs (and to a greater extent

I really hope they open source their compiler and allow people to program directly to the machine code. Part of the problem with GPUs (and to a greater extent FPGAs) is that the toolchains are often terrible, buggy and opaque. They also make it really hard for people to write easier abstractions on top of them. I guess CUDA does do better along many of those axes than alternatives at the cost of being vendor-specific, but anything for this would be vendor-specific too. So much code we write doesn't take advantage of GPU power because it's harder to program for and also you pay a latency cost for transmitting your data to/from the GPU. If this architecture makes GPU-style programming easier in that you just switch to using a different style of programming in the middle of your code and the CPU just uses different instructions without a big latency penalty that would be very cool.

justicezyx 7y ago
MLIR might contribute to improve the situation. Especially after Chris Lattner joined SiFive, which should give it a strong push to adopt the technology in RISC-V & its extensions ecosystems.
joe_the_user 7y ago
You can look at Nvidia PTX as well as cuda. Ptx is their macro assembler code (still higher level than machine but translated by the chip itself I think). As far as open sourcing the compiler, I suspect that having good documentation about what all the low-level instruction do would be as important if not more important than compiler source code. Just the compiler code wouldn't tell you why they do a given set of operation. Moreover, if a group is designing the chip and compiler together, you may wind-up with a situation where they only know the compiler stuff works, they don't know what happens if you do various other things.
- verall 7y ago
  The ptx is jit by the gpu driver for your device's specific architecture but it's pretty fast. If you know you are targeting a specific device it's possible to aot compile your ptx.
ur-whale 7y ago
> really hope they open source their compiler and allow people to program directly to the machine code. Be careful what you wish for. Writing compilers (and hand-coded assembly) for theses types of 'poison bit' architectures is not for the faint of heart.
- salawat 7y ago
  >'poison bit' architecture... I've never heard that phrase before. Got any reading material on it?

justicezyx 7y ago

MLIR might contribute to improve the situation. Especially after Chris Lattner joined SiFive, which should give it a strong push to adopt the technology in RISC-V & its extensions ecosystems.

joe_the_user 7y ago

You can look at Nvidia PTX as well as cuda. Ptx is their macro assembler code (still higher level than machine but translated by the chip itself I think). As far as open sourcing the compiler, I suspect that having good documentation about what all the low-level instruction do would be as important if not more important than compiler source code. Just the compiler code wouldn't tell you why they do a given set of operation. Moreover, if a group is designing the chip and compiler together, you may wind-up with a situation where they only know the compiler stuff works, they don't know what happens if you do various other things.

verall 7y ago
The ptx is jit by the gpu driver for your device's specific architecture but it's pretty fast. If you know you are targeting a specific device it's possible to aot compile your ptx.

ur-whale 7y ago

> really hope they open source their compiler and allow people to program directly to the machine code. Be careful what you wish for. Writing compilers (and hand-coded assembly) for theses types of 'poison bit' architectures is not for the faint of heart.

salawat 7y ago
>'poison bit' architecture... I've never heard that phrase before. Got any reading material on it?