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> where as if you go RISC-V, you are free to switch CPU providers. Idk, this really isn't as true as you'd think. Yes RISC-V is an open and free ISA which will

> where as if you go RISC-V, you are free to switch CPU providers. Idk, this really isn't as true as you'd think. Yes RISC-V is an open and free ISA which will cut out some fees, but you'd still have to license IP/chip designs (if you can't make your own) and they could only undercut ARM by a little bit. Further, the lack of mobility across chips/boards/whatever is not usually from the ISA, but from the BSP, SDK, etc. so you still would have substantial lockin unless we somehow standardize on that (lol)

aristus 3y ago
You're not wrong, but having two choices of supply does wonders for squeezing profit margins from both back to the customer. Duopolies are terrible but better than monopolies.
pclmulqdq 3y ago
ARM actually has a pretty good story for how they can undercut RISC-V prices in that they can design the ISA rather than accepting the decisions of a committee. That committee used to make good choices, but things like the vector ISA seem more suspect.
- packetlost 3y ago
  The general consensus I've heard is the vector extension is good? I do agree the design by committee is less than ideal, but the ability to add vendor extensions at all is nice for certain markets.
- monocasa 3y ago
  The vector ISA seems alright to me. Particularly compared to Neon, but even compared to SVE.
AnthonyMouse 3y ago
Part of the issue here is that nobody is going to build something free on top of someone else's property. What good is a "free" design if you still have to pay ARM? Whereas once you have a free ISA which is actually in widespread use, you could get some designs out of universities or major corporations which intend to use them rather than sell them as their primary business and then release the design for the same reason they do for Linux code, potentially under a copyleft-style license. Those designs aren't going to be competitive with the state of the art, at least in the beginning, but they don't have to be. All they have to be is low power enough to stick in an embedded device and fast enough to run the display on a refrigerator and the lack of a license fee would cause them to replace a zillion ARM chips that currently go into every IoS device and <$200 phone and consumer internet router. That's a huge chunk of ARM's market. Then someone like Amazon evaluates this thing for something like the Kindle and finds that it's almost good enough, all they have to do is throw a couple of engineers at it for a short period of time, so they do and it gets released because what do they care of some non-competitor uses it in some cheap laptop. Commoditize your complement -- now laptops are cheaper and people buy more laptops on Amazon. Meanwhile the "small project" uncompetitive boards start to have their own open source BSP and SDK under the BSD license, which means anybody else can fork it for their own thing, and that's a competitive advantage so it happens a lot. But now it's way easier to reverse engineer the code because 95% of it is unmodified, so you start getting community replacements for that stuff and with any luck the OEMs stop even producing it and point you to the open source repository. It could be a long time before that takes over the high end, if that ever happens, but the low end? It's almost inevitable. And the high end is AMD64 and Apple, the latter of which has all the leverage in the world over ARM because they could always switch to RISC-V.
- doctorpangloss 3y ago
  As a layperson though, how would I be able to tell whether any of this is true? When I have to target platforms as a software developer, the truth is, I’ll do whatever Microsoft and Apple tell me to. By the time Apple is shipping a RISC-V phone I hope to be retired!
  - AnthonyMouse 3y ago
    For any kind of high-level code, "platform" is something like win32 or Android or Qt. The underlying hardware architecture is the compiler/interpreter's problem. The people dealing with assembly know who they are, but much of that is the sort of work that cares a lot about shaving off a few cents worth of license fee for an embedded device.
    - WanderPanda 3y ago
      Until it becomes the users problem (e.g. PowerPC -> Intel -> ARM transitions)
      - AnthonyMouse 3y ago
        For users of general purpose computers this is caused almost entirely by closed-source software. Most of the architecture-specific code is part of the operating system, and by the time you're doing an architecture transition the OS itself runs on the new architecture. The third party applications largely aren't dependent on a specific architecture but they're compiled for one. With open source you could just recompile for the new architecture. Linux has always run on just about every one under the sun and the user largely can't even tell the difference. But if you don't have the source code you can't do that. Closed-source systems could avoid this by compiling to bytecode, which is essentially what Android does, so transitioning to RISC-V would be much less trouble there than it would be for e.g. Windows.
  - smoldesu 3y ago
    > As a layperson though, how would I be able to tell whether any of this is true? You probably won't ever know. Do you know the architecture of the microcontroller on your first computer's hard drive? I don't. The stuff that RISC-V will replace first is the low-margin hardware that can be mass-produced by China et. al and exported without license violation. ARM's goose was already cooked in this sense, and even ARM China won't fix it. For IO controllers, ICs and network switches, it's hard to see why manufacturers would stick with higher-margin ARM hardware. If RISC-V cores are cheap, stable and available, you could replace them without the user ever noticing. > By the time Apple is shipping a RISC-V phone I hope to be retired! Apple is reportedly looking to replace some of their A-series ICs with RISC-V ones: https://www.techpowerup.com/298936/report-apple-to-move-a-part-of-its-embedded-cores-to-risc-v-stepping-away-from-arm-isa https://www.techpowerup.com/298936/report-apple-to-move-a-pa... Hopefully you don't intend to retire this soon :p

aristus 3y ago

You're not wrong, but having two choices of supply does wonders for squeezing profit margins from both back to the customer. Duopolies are terrible but better than monopolies.

pclmulqdq 3y ago

ARM actually has a pretty good story for how they can undercut RISC-V prices in that they can design the ISA rather than accepting the decisions of a committee. That committee used to make good choices, but things like the vector ISA seem more suspect.

packetlost 3y ago
The general consensus I've heard is the vector extension is good? I do agree the design by committee is less than ideal, but the ability to add vendor extensions at all is nice for certain markets.
monocasa 3y ago
The vector ISA seems alright to me. Particularly compared to Neon, but even compared to SVE.

AnthonyMouse 3y ago

Part of the issue here is that nobody is going to build something free on top of someone else's property. What good is a "free" design if you still have to pay ARM? Whereas once you have a free ISA which is actually in widespread use, you could get some designs out of universities or major corporations which intend to use them rather than sell them as their primary business and then release the design for the same reason they do for Linux code, potentially under a copyleft-style license. Those designs aren't going to be competitive with the state of the art, at least in the beginning, but they don't have to be. All they have to be is low power enough to stick in an embedded device and fast enough to run the display on a refrigerator and the lack of a license fee would cause them to replace a zillion ARM chips that currently go into every IoS device and <$200 phone and consumer internet router. That's a huge chunk of ARM's market. Then someone like Amazon evaluates this thing for something like the Kindle and finds that it's almost good enough, all they have to do is throw a couple of engineers at it for a short period of time, so they do and it gets released because what do they care of some non-competitor uses it in some cheap laptop. Commoditize your complement -- now laptops are cheaper and people buy more laptops on Amazon. Meanwhile the "small project" uncompetitive boards start to have their own open source BSP and SDK under the BSD license, which means anybody else can fork it for their own thing, and that's a competitive advantage so it happens a lot. But now it's way easier to reverse engineer the code because 95% of it is unmodified, so you start getting community replacements for that stuff and with any luck the OEMs stop even producing it and point you to the open source repository. It could be a long time before that takes over the high end, if that ever happens, but the low end? It's almost inevitable. And the high end is AMD64 and Apple, the latter of which has all the leverage in the world over ARM because they could always switch to RISC-V.

doctorpangloss 3y ago
As a layperson though, how would I be able to tell whether any of this is true? When I have to target platforms as a software developer, the truth is, I’ll do whatever Microsoft and Apple tell me to. By the time Apple is shipping a RISC-V phone I hope to be retired!
- AnthonyMouse 3y ago
  For any kind of high-level code, "platform" is something like win32 or Android or Qt. The underlying hardware architecture is the compiler/interpreter's problem. The people dealing with assembly know who they are, but much of that is the sort of work that cares a lot about shaving off a few cents worth of license fee for an embedded device.
  - WanderPanda 3y ago
    Until it becomes the users problem (e.g. PowerPC -> Intel -> ARM transitions)
    - AnthonyMouse 3y ago
      For users of general purpose computers this is caused almost entirely by closed-source software. Most of the architecture-specific code is part of the operating system, and by the time you're doing an architecture transition the OS itself runs on the new architecture. The third party applications largely aren't dependent on a specific architecture but they're compiled for one. With open source you could just recompile for the new architecture. Linux has always run on just about every one under the sun and the user largely can't even tell the difference. But if you don't have the source code you can't do that. Closed-source systems could avoid this by compiling to bytecode, which is essentially what Android does, so transitioning to RISC-V would be much less trouble there than it would be for e.g. Windows.
- smoldesu 3y ago
  > As a layperson though, how would I be able to tell whether any of this is true? You probably won't ever know. Do you know the architecture of the microcontroller on your first computer's hard drive? I don't. The stuff that RISC-V will replace first is the low-margin hardware that can be mass-produced by China et. al and exported without license violation. ARM's goose was already cooked in this sense, and even ARM China won't fix it. For IO controllers, ICs and network switches, it's hard to see why manufacturers would stick with higher-margin ARM hardware. If RISC-V cores are cheap, stable and available, you could replace them without the user ever noticing. > By the time Apple is shipping a RISC-V phone I hope to be retired! Apple is reportedly looking to replace some of their A-series ICs with RISC-V ones: https://www.techpowerup.com/298936/report-apple-to-move-a-part-of-its-embedded-cores-to-risc-v-stepping-away-from-arm-isa https://www.techpowerup.com/298936/report-apple-to-move-a-pa... Hopefully you don't intend to retire this soon :p