Experts at the Table: Extensible instruction-set architecture is drawing attention from across the industry and supply chain.

Ed Sperling, Semiconductor Engineering

July 30, 2020

Part 1: Semiconductor Engineering sat down to discuss where and why RISC-V is doing well, with Zdenek Prikryl, CTO of Codasip; Helena Handschuh, a Rambus Security Technologies fellow; Louie De Luna, director of marketing at Aldec; Shubhodeep Roy Choudhury, CEO of Valtrix Systems; and Bipul Talukdar, North America director of applications engineering at SmartDV. What follows are excerpt of that conversation.

SE: Where are you seeing RISC-V gaining traction, and has that shifted over the past year?

Handschuh: You can see from all the different companies that are participating in the RISC-V Foundation and RISC-V International that most of the people who have embedded systems and who are designing and making chips are trying their own little prototype first. They are trying to figure out if RISC-V could could be useful for migrating it toward all of their products. Nvidia, NXP, Rambus and Qualcomm are all working on concepts. So are companies like Alibaba and Huawei. Everybody is trying it out, and for those that are successful, you probably can expect them to more of these designs in the future.

Talukdar: Yes, and where I see RISC-V gaining traction is not for huge applications at the moment. It’s more where you need a specialized accelerator or something like that. The RISC-V platform gives you a standard, open-source kind of platform, and then the user builds a specialized application and actually can extend the ISA. That will fit into the RISC-V architecture, where the general-purpose computing will happen on their standard open-source RISC-V cores, and the accelerator will do the job for their custom applications. That will grow over time. There also are companies that are building RISC-V applications that cater to the data centers and the server businesses., but those are not part of the main trend yet.

De Luna: We’re also seeing a possibility that RISC-V can move into mission-critical systems, since it’s fully open and they have the RTL source code available to check and test. That makes it easier for design and implementation in terms of transparency, and it enhances trust. Right now, integrators rely on blind trust. With open source and full RTL source code, they don’t have to do that anymore.

Roy Choudhury: Regions like Southeast Asia and China are definitely seeing a surge in the adoption of RISC-V for several reasons. Some people want to have a hold on designs and do things on their own. There is always a risk of back doors when you’re taking IP from other companies. RISC-V gives you a lot of freedom and independence. With other companies, you are bound by agreements not to make any changes. With RISC-V, you already have very good base reference designs available, so you could freely go ahead and make some changes and publish it as a custom extension for your own design. That gives you flexibility to add add new features, which is not possible with other ISA architectures at this moment. So definitely this a wave, and it’s not just about China. We are seeing adoption across the globe.

Prikryl: China is really active right now. In fact, it is the most active territory at the moment. With RISC-V, we see a lot of traction at the universities and in the companies. Pretty much every company has some kind of RISC-V strategy. Either they have adopted RISC-V already or plan to quite soon. The next one from a geographical point of view is North America. The U.S. is quite active. You can see startups working with RISC-V in AI domains because you need to have some kind of customization. RISC-V is very well positioned for that. Europe is also also strong, especially in the universities. And last but not least, there is activity in places like Israel and Japan, although not as much as in China or America.

SE: China opens up some interesting options for RISC-V because of the emphasis on a separate supply chain and the potential for lower design costs. How does that affect the market?

De Luna: The escalation of the U.S.-China trade war is definitely triggering more interest in RISC-V in China. Huawei announced a year ago, before the COVID-19 outbreak, that they were considering RISC-V as a backup in case Arm’s cores become unavailable to them. Huawei is already a premium member of RISC-V, so there’s really traction there. Last year, Alibaba released the RISC-V core, and they claim it is the fastest in the market right now. It’s 64-bit, 2.5GHz at 12nm. And there’s already a couple of RISC-V groups in China.

Handschuh: And there’s less of a feeling of being locked down to something specific. You don’t have to ask permission for any variations or variants you want to do. You don’t really need big architecture licenses. So it gives you more freedom to operate and to invent your own extensions, if that’s useful for you or for your specific market. So from a cost perspective, it’s very interesting, and then people try it out and they migrate to it. They first want to see if it’s going to work for them, and so far we’ve seen some interesting results. There are some good initiatives.

Roy Choudhury: In order for RISC-V to become competitive, we need a lot more people working on it and putting ideas into it. If a lot of people are contributing, it will have good momentum and will be able to scale very well. So I certainly see that as a positive. And of course, whenever we people contribute they make some contributions to the open source community, as well. This will benefit RISC-V in the long term.

Prikryl: Thanks to RISC-V’s open ISA and micro-architectural implementations being unrestricted, you see a lot of start-ups, big companies and open source companies that have designed or are designing RISC-V processors from scratch in China. They are contributing to the open source community as well. The Hummingbird project is a nice example of an open source project that is popular there. RISC-V is an opportunity to develop new processors, and shows a growing Chinese interest in processor design in general.

Talukdar: I attended like conference in China and I have seen up close the enthusiasm around RISC-V, and the enthusiasm around being able to build things in-house, in their own facilities. Chinese companies already are good at doing the hardware stuff, but owning the IP and being able to design it on their own — that’s where the real drive is. That’s also coming from up high on the political side, and they’re investing so that they can own more of this IP. RISC-V gives them a huge advantage, because with an extendable ISA you can build you specialized processors and SoC applications. And with the help they can get from the open-source community, and the companies that are driving development around open source and providing design services on top of it, that makes it very attractive for companies in China to tap into. So they can take all the help they can get, and at the same time develop something on their own and eventually to become be independent.

SE: Another big market opportunity involves AI and the edge, both of which are new and still evolving markets. Does RISC-V have a role to play there? And if so, where?

Prikryl: It does, and it’s not just for startups. It’s also big guys like Alibaba and Western Digital. Either they have a strategy or they have it in their hands already. In the application domains you can see a really wide range of developments. A RISC-V ISA can be in everything from a small microcontroller to data center processors that run Linux. It’s not completely there yet, but it will be soon. In our case, we’re seeing an uptake in AI, because AI is a moving target and we can adapt it very fast.

De Luna: At the intersection between AI and edge there’s really a lot of promise for for RISC-V. In the IoT nodes, the available memory and power are very limited. But at the same time, even the simplest AI algorithms require memory and power. One solution here is approximate computing, and there are some specialized approximate arithmetic blocks being used in the data path to reduce power consumption and latency. This blocks are using RISC-V custom instructions like approximate add, subtraction and multiplication for calculating specific parts of the code.

Roy Choudhury: We already are seeing a lot of traction in the AI space with respect to RISC-V. But it’s not just restricted to AI. There is good adoption in other areas, too, like the microcontroller space. Working with other customers, we see a lot of other use cases, as well, which are coming in very fast. When there are more architectural features available, people will start to see general-purpose computers made out of this, too.

Handschuh: RISC-V is really not so different here. It can allow you to do any type of implementation for any type of market. That’s because of the possibility to make extensions to the ISA, and so it can adapt to what you need. You can do root-of-trust products on RISC-V and use it at the edge to secure the device, and help you protect the data and do secure inferencing and things like that. I would actually argue it gives you a bit more latitude to operate in new areas where new requirements are showing up and coming coming around because you can innovate around it very easily.

Talukdar: And it’s not just China and AI. In India, there is an indigenous processor development project going on at the Indian Institute of Technology. There has been a bid drive in India to do these kinds of things indigenously, but it hasn’t really gone on at scale yet. RISC-V opens up loads of opportunities for development that’s happening today in India. It would not be a surprise to see India coming out with a brand-new, from-scratch SoC based on RISC-V.

This article was originally published in Semiconductor Engineering