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I expect RISC-V to match Apple's ARM implementations efficiency/speed within the decade. This is a long time but it is a very lofty goal as Apple's ARM impleme

I expect RISC-V to match Apple's ARM implementations efficiency/speed within the decade. This is a long time but it is a very lofty goal as Apple's ARM implementation is a moving target to RISC-V has to move faster. But it likely will come close to converging around 5 years from now -- at least somewhat competitive in core count and single core performance. Interesting times. I look forward to the first AMD Ryzen-like chipset designs for ARM and RISC-V. That is an innovation that is just waiting to be taken advantage of by these newer architectures.

alexhutcheson 6y ago
That might be true, but I wouldn't expect the microarchitectures that achieve this performance to be free (in either the "gratis" or "libre" senses of that word). Designing a superscalar application processor requires an enormous amount of work by engineers who are experts in their field, and that work needs to be compensated somehow. The ISA may be open, but there is no requirement for the microarchitecture implementing the ISA to be, and it's hard to imagine anyone doing the work to produce a performance-competitive chip and then giving it away. Even if there is a "consortium" model where multiple companies benefit from a single design, they would likely set up some sort of licensing arrangement to prevent free-riding by companies that did not contribute to the design.
- tipsysquid 6y ago
  > I wouldn't expect the microarchitectures that achieve this performance to be free (in either the "gratis" or "libre" senses of that word) I agree with you on this as an eventuality of risc-v. But my casual following of the space leads me to believe that a high-performance open baseline of these architectures will be available and customization/special purpose of these archs will be for purchase. I'm hopeful some of the benefits will be contributed upstream. As long as there is some competition in the architecture space (ARM, x86, risc-v), the more likely builders will share gains upstream to compete against rival platforms. That's my wishful thinking at least.
  - alexhutcheson 6y ago
    I think you’re likely underestimating how complex a modern microarchitecture like the A78 or X1 is compared to the RISC-V cores that have been open sourced so far. It’s unclear to me what organizations would have the resources to develop something like the A78 for RISC-V and would also be happy giving it away for free. Note that in the ARM world everyone except Apple and Nvidia have given up on developing their own microarchitectures - they all just license one from ARM and maybe apply some customizations on top.
- nickik 6y ago
  There are benefits to having an Open ISA even without all cores being open.

alexhutcheson 6y ago

That might be true, but I wouldn't expect the microarchitectures that achieve this performance to be free (in either the "gratis" or "libre" senses of that word). Designing a superscalar application processor requires an enormous amount of work by engineers who are experts in their field, and that work needs to be compensated somehow. The ISA may be open, but there is no requirement for the microarchitecture implementing the ISA to be, and it's hard to imagine anyone doing the work to produce a performance-competitive chip and then giving it away. Even if there is a "consortium" model where multiple companies benefit from a single design, they would likely set up some sort of licensing arrangement to prevent free-riding by companies that did not contribute to the design.

tipsysquid 6y ago
> I wouldn't expect the microarchitectures that achieve this performance to be free (in either the "gratis" or "libre" senses of that word) I agree with you on this as an eventuality of risc-v. But my casual following of the space leads me to believe that a high-performance open baseline of these architectures will be available and customization/special purpose of these archs will be for purchase. I'm hopeful some of the benefits will be contributed upstream. As long as there is some competition in the architecture space (ARM, x86, risc-v), the more likely builders will share gains upstream to compete against rival platforms. That's my wishful thinking at least.
- alexhutcheson 6y ago
  I think you’re likely underestimating how complex a modern microarchitecture like the A78 or X1 is compared to the RISC-V cores that have been open sourced so far. It’s unclear to me what organizations would have the resources to develop something like the A78 for RISC-V and would also be happy giving it away for free. Note that in the ARM world everyone except Apple and Nvidia have given up on developing their own microarchitectures - they all just license one from ARM and maybe apply some customizations on top.
nickik 6y ago
There are benefits to having an Open ISA even without all cores being open.