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Comment by Fordec | Hacker News Reader

If RISC-V is just their platform to provide a different company to license IP from, I'm just sticking to Arm.

RISC-V is only interesting as a platform for a different business model.

The biggest benefit of RISC-V is that you are not married to a single IP vendor.

If ARM decides to change their license terms, you are screwed. If SiFive decides to change their license terms, you could just switch to a competing IP vendor without any changes to your software ecosystem.

ARM seems to be half-way moving in this direction. They allowed "royalty free" licenses to educational institutions for some of their low end M0/3/4 cores. But yeah, I think you're right. The cool thing about RISC-V is you can just pick up the ISA and run with it. I'm pretty sure the Rocket core generator is released under a BSD license. SiFive sort of makes sense if you want to integrate proprietary IP with open IP, and some people do actually want to do that. I don't know if there's enough demand for that, though.

But yeah. Even though we have compilers, it's not like you can spin up support for a new ISA in the drop of a hat. If you launched a project with a StarFive part and then decided you wanted to use SiFive IP, you should be able to use the same tooling. The impact of that shouldn't be under-estimated.

That's an important advantage: go Arm, and ultimately you'll be dealing with Arm (the IP licensing company), or with a 3rd party which deals with them.

Go x86, and you'll end up dealing with Intel, or AMD (okay, there's Via & maybe a few makers of legacy x86 parts).

Go RISC-V, and roll your own or pick from a growing list of vendors, are both valid options. And switch supplier while keeping your toolchain ecosystem.

I'd expect at least that this will spur innovation in the field. Likely increase consumer choice.

More suppliers of [insert product type here] is almost always a good thing.

RISC-V is only a basic CPU specification, everything else is vendor specific.

RISC-V, as of current ratified specifications, is anything but basic: It has feature parity with x86 and ARM.

And the specs extend further to non-ISA, such as standardizing boot process and platform.

If we forget about everything else needed to put that paper specification on a real motherboard.

The important part is from a software perspective, none of that stuff matters much. The benefit of RiscV is you can be sure that your low level software (e.g. an OS or HPC thing that requires hand coded assembly) won't be tied to a specific company's hardware.

I read your comment to imply that the ISA is the only thing that matters since that's what defines the software interface and that software is the only thing that matters.

If that is what you're saying, I think you're wrong.

As to the low level hand coded assembly. There's a fair amount of stuff in the Intel architecture that's not officially published. There are tools (from Intel) like VTune and the Intel C compilers that use non-published interfaces to optimize C or assembly, sometimes significantly. It is true you can write software without them, but many people purchase these Intel tools to make sure their systems run quickly and efficiently.

I can't remember if the SiFive U-X4 core equivalents were defined in the open RISC-V specs or as part of SiFive specific interfaces. If the former, then your point is even stronger. If the latter, your point is still valid, though modulo the impact of having relied on a SiFive specific interface.

Ignoring extensions and motherboard features used from userspace.

Or... like my team did... you can design your own IP that specifically fits your needs.

Depends on the extensions being used, and board designs.

For sure, but I guess you're not in SiFive's target market. You're not a customer of Arm either, unless you are licensing chip designs from Arm. Someone who merely buys Arm chips is a customer of the company that licenses from Arm, not of Arm.

Nevertheless it seems plausible there are companies that would like to license a RISC-V design (rather than implement their own or use one of the slower free cores) and might therefore be a SiFive customer. I'm not saying it's going to be a huge market, probably a much smaller one even than Arm, but it's a possible one.

Very true. I'm not in SiFive's target market. Though I do use M0 and M4 cores fairly frequently. But I'm not a direct customer of ARM, though. I think that's what you were implying.

I think part of what I'm getting at is it's TOUGH to get people to adopt new IP. And it's TOUGH to be all things to all people so you can compete in the low end against M0s and MSP430s, in the mid range against A77s and in the high end against i9's.

That being said, if SiFive fabbed a catalog part with one or two E20s at a reasonable cost, I have an immediate need of 200 of them. I only wish there were another 500 of me with a similar need so there was a chance we could get it fabbed at a decent price.

> if SiFive fabbed a catalog part with one or two E20s at a reasonable cost

Why would they do that? That's not the business SiFive is in. Arm doesn't do that -- they leave that to people such as the Raspberry Pi Foundation with the RP2040.

Perhaps (if you insist on a SiFive core) you could look at something like the BL602? $0.99 here.

https://pine64.com/product/pineseed-bl602-wifi-ble5-soc/

If you're willing to use non-SiFive cores (and why not), the CH32V003 is pretty awesome for $0.10 (8 pin) to $0.14 (20 pin), assuming 2K RAM and 16K flash is enough for your purposes.

But I don't know what is "a decent price" for you.

Jim Keller's Tenstorrent worked with SiFive instead, because ARM didn't want to customize their cores for machine learning workloads and now they are developing a RISC-V with a ridiculous performance profile.

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