from Hacker News

RISC-V Pros and Cons

by englishm on 5/31/17, 2:04 PM with 44 comments

• by Nokinside on 5/31/17, 3:39 PM

  > It tries to undercut the ARM model of establishing how CPUs or other cores should work and how they should be valued.”

  Companies are not going for ARM just to license professor ISA's. They also license and value the underlying efficient and high performance architecture ARM has developed.

  What can happen with RISC-V is that there are several competing IP companies that develop competing RISC-V architectures and ask royalties and license fees for their IP. This competition can bring down the cost somewhat. If ARM royalty is 1.5% today, the cost may be 0.77% in the future. It's also possible that one company will dominate others with superior design, price and foundry connections. That company might be ARM, AMD or Intel.

• by gumby on 5/31/17, 5:55 PM

  I'm excited by RISC-V. It has some interesting architectural decisions.

  Remember the ARM started in the 1980s was solid but not a breakout architecture until the early 2000s. The x86's roots lie in the 70s and it took a killer app (IBM PC) to make it dominant. GCC took about a decade to get any traction.

  So it's early days for RISC-V

• by tgragnato on 5/31/17, 3:14 PM

  An issue that's not mentioned is memory consistency. It's not something that's going to solve without $$, and may pose a serious economical obstacle.

  EDIT: coherence -> consistency (sorry)

• by sweden on 5/31/17, 4:49 PM

  People like to compare RISC-V to Linux, which I think it is just wrong.

  Linux is something that you can download from kernel.org, compile it and bring it up over night. It's a package with a bunch of scripts that compiles a working kernel for your machine. All the work is already done for you.

  RISC-V, on the other hand, it is just a document describing an ISA. It is far different from a working implementation.

  RISC-V might shine on micro-controllers and on power management control units, since those applications are more simple and more affordable to implement from scratch.

  But on high-end applications, it will be no different from ARM's path. Implementing an high performant CPU costs money, someone will have to cater those costs, either by hiring a full team of highly specialized engineers (which will cost a bunch of money) or by licensing to third parties (which will also cost money through licenses or royalties).

• by morio123 on 5/31/17, 5:33 PM

  "Not everything exists for RISC-V that exists for the other ones, but that is filling in at incredible pace."

  The RISC-V project is now 7 years old. Remember that the 6502 and its supporting hardware went from proposal to final silicon in 2 years. And that was done using a hand drawn layout.

• by redtuesday on 5/31/17, 4:15 PM

  Could a chip based on the SuperH ISA (off which the patents expire) [0] like JCore compete with RISC-V if similar effort would be put into it?

  [0] https://en.wikipedia.org/wiki/SuperH

• by mjevans on 5/31/17, 2:59 PM

  I didn't read the article, but I have been trying to stay vaguely informed off and on.

  The two 'cons' that really need to be addressed:

  * Average consumers need /access/ to purchase working solutions (which means some prosumers and some developers will).

  * Working solutions probably need to include: DisplayLink, USB, Ethernet, and /maybe/ WiFi (the later two /could/ just be USB devices) ports on the hardware. Standard bulk IO (like SATA, PCI(e) bus) would be nice to have, but not required.