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> RiscV is going to win despite its limitations, simply because they can be worked around freely, and the cost per core is zero. This feels right to me. I've w

> RiscV is going to win despite its limitations, simply because they can be worked around freely, and the cost per core is zero. This feels right to me. I've worked on embedded systems and OS my whole career and it just doesn't really feel like riscv wins or loses on technical merit to me. Boots-on-the-ground engineers might grumble but the decisions that matter here just aren't made by them. Otherwise why would we still be using x86 so much? I've worked on platforms that had barely-functional CPUs, we had to regularly be in touch with the engs that implemented them and they'd regularly go "oh yeah you've found a bug in our memory subsystem". This was kinda annoying for us but those CPUs were cheap as fuck and that opened up business models that weren't otherwise available. This is always gonna be more important than "ah but the CPUs are suboptimal!!"

mike_hearn 1mo ago
We use x86 because the implementations are fast and there's so much software encoded with it. This makes up for the problems of the design. RISC-V doesn't have either of those advantages, though.
- bjackman 1mo ago
  Yeah my x86 comment wasn't meant to suggest RISCV can easily beat x86 it was pointing out that "being a good arch" is very low on the list of priorities for making the arch successful. Exactly as you say, x86 is successful coz there are really good x86 CPUs and a SW ecosystem. Not because it's a good arch. Similarly I think, if it wins, RISCV will win because there's enough demand for a nonproprietary ISA, and this trumps basically everything else. Another way to say this: I've seen internal slide decks about ISA strategy that target C-suites at megacorps. Not once do those slide decks ever go into technical dis/advantages, coz the people steering the 9-figure investments don't give a shit. If you piped up in those meetings and said "RISCV sucks though!!!" you would just be ignored and not invited back. It's not really any different from startups. Tech stacks matter but there's a huge number of successful companies out there running total garbage and who knows how many perfectly engineered products go out of business every day coz the thing they perfectly engineered was not useful.
ndiddy 1mo ago
You're agreeing with the conclusion the original article makes: > None of this is to say that RISC-V is doomed. As I said, I fully expect it to take over the space currently occupied by 8051 as a typical cheap embedded core instantiated when some small amount of logic is needed, or some beefy accelerator or DMA engine needs some mild babysitting. Much like the linux kernel -- the price is right. ARM wants licensing fees, while the RISC-V spec is free, and (this part is key) there are cores out there which can be licensed for free. For situations where performance is not a factor and price is, RISC-V will win simply due to its price. "Good-enough" is a low bar in this case, and RISC-V is of the right height to meet it. And look, this market is not glorious, but it matters and it needs new blood. However, it is important that RISC-V not accidentally think it was chosen for being good. It needs to internalize that it was chosen for being cheap. This is not meant as an insult to cheap small cores -- I've written plenty of assembly for all sorts of shitty cores with shittily designed ISAs. RISC-V is an improvement over PIC and 8051, as little of a compliment as that is. RISC-V may be suboptimal, but it's a lot better than 8051 and you can use GCC instead of having to buy Keil licenses for all your developers. Meanwhile at the higher end (desktops and higher-end SBCs), you'll still have to pay for a quality out-of-order core even if the ISA is free, and you have to deal with binary compatibility being more important. I can see RISC-V being a massive success on the low end, and displace 8051 and maybe Cortex-M0. However, I don't think this means that it'll be able to displace ARM64 on the high end.

mike_hearn 1mo ago

We use x86 because the implementations are fast and there's so much software encoded with it. This makes up for the problems of the design. RISC-V doesn't have either of those advantages, though.

bjackman 1mo ago
Yeah my x86 comment wasn't meant to suggest RISCV can easily beat x86 it was pointing out that "being a good arch" is very low on the list of priorities for making the arch successful. Exactly as you say, x86 is successful coz there are really good x86 CPUs and a SW ecosystem. Not because it's a good arch. Similarly I think, if it wins, RISCV will win because there's enough demand for a nonproprietary ISA, and this trumps basically everything else. Another way to say this: I've seen internal slide decks about ISA strategy that target C-suites at megacorps. Not once do those slide decks ever go into technical dis/advantages, coz the people steering the 9-figure investments don't give a shit. If you piped up in those meetings and said "RISCV sucks though!!!" you would just be ignored and not invited back. It's not really any different from startups. Tech stacks matter but there's a huge number of successful companies out there running total garbage and who knows how many perfectly engineered products go out of business every day coz the thing they perfectly engineered was not useful.

ndiddy 1mo ago

You're agreeing with the conclusion the original article makes: > None of this is to say that RISC-V is doomed. As I said, I fully expect it to take over the space currently occupied by 8051 as a typical cheap embedded core instantiated when some small amount of logic is needed, or some beefy accelerator or DMA engine needs some mild babysitting. Much like the linux kernel -- the price is right. ARM wants licensing fees, while the RISC-V spec is free, and (this part is key) there are cores out there which can be licensed for free. For situations where performance is not a factor and price is, RISC-V will win simply due to its price. "Good-enough" is a low bar in this case, and RISC-V is of the right height to meet it. And look, this market is not glorious, but it matters and it needs new blood. However, it is important that RISC-V not accidentally think it was chosen for being good. It needs to internalize that it was chosen for being cheap. This is not meant as an insult to cheap small cores -- I've written plenty of assembly for all sorts of shitty cores with shittily designed ISAs. RISC-V is an improvement over PIC and 8051, as little of a compliment as that is. RISC-V may be suboptimal, but it's a lot better than 8051 and you can use GCC instead of having to buy Keil licenses for all your developers. Meanwhile at the higher end (desktops and higher-end SBCs), you'll still have to pay for a quality out-of-order core even if the ISA is free, and you have to deal with binary compatibility being more important. I can see RISC-V being a massive success on the low end, and displace 8051 and maybe Cortex-M0. However, I don't think this means that it'll be able to displace ARM64 on the high end.