RISC-V, the instruction-set architecture out of UC Berkeley, has been making waves in the semiconductor sector. Some even say that it could threaten industry heavyweight ARM in the long run.
The key difference between the pair’s respective products, which basically define the way in which software talks to a processor, is that RISC-V is open-source. It is this aspect that could be of particular interest to Chinese companies as such products are not directly subjected to US sanctions.
The RISC-V Foundation, which promotes the ISA’s use, features leading global players including Microchip, Western Digital, Google, Nvidia, and Qualcomm, to name just a few. Through collaborative and independent projects, several members are working to create RISC-V based designs.
China’s growing interest
Over the past few years, and especially in 2019, I have witnessed a huge increase in Chinese interest in RISC-V. Three years ago when mentioning the ISA, most engineers would look at me puzzled. Then, two years ago, they had at least heard of it though most would mispronounce it (it’s Risk-Five by the way).
Fast-forward to today and not only does every company I meet know of it, but the majority are actively researching it. Whether they have taped out an actual RISC-V based chip or are currently designing one, the interest is clearly there.
Today the foundation includes more than 25 Chinese companies, and what’s more, as of last year China now has two of its own RISC-V industry alliances with more than 185 members. Some of the most well-known Chinese members include Huawei, Sanechips from ZTE, Bitmain, Alibaba, and Xiaomi’s wearables partner Huami.
So, what’s all the fuss about? Why are so many large global companies jumping on the bandwagon, and what does RISC-V mean for China?
RISC-V provides an open-source ISA which users can build upon. As its a frozen ISA, software designed to run on one RISC-V processor will run on any other. It also provides a processor business model similar to that of Linux. Commercial vendors can build on the open-source ISA, or open-source cores to create their own IP to license and support.
It is important to note that whilst RISC-V is open-source, any serious product is probably going to want to license a commercial RISC-V core. Alternatively, companies with the resources and expertise can design their own. Often people may misunderstand RISC-V to be free. It isn’t but it is cheaper. Some commercial core suppliers do not ask for royalties, and license fees can be low, especially as these suppliers try to gain market share.
The main barrier to entry in the RISC processor world has been less technical and more ecosystem-related. Whilst ARM has a much more mature and sizeable ecosystem, that of RISC-V is growing fast and within these short few years, there are already products based on the ISA in the market and a supporting ecosystem.
While India has adopted more of a central government approach, China’s local authorities appear to actively compete in the semiconductor space, and we are now seeing RISC-V specific investments in the form of grants from the Shanghai and Nanjing governments among others. While what the Indian government is doing is great, China and its large number of semiconductor designers and household names are much better placed to take advantage of opportunities presented by RISC-V.
An interesting aspect of RISC-V to China is that it is not covered by the US Entity list as it is open-source. This means Chinese companies can use it without any fear of losing access in the future. Even SiFive, the first commercial RISC-V core company, and from the US, can still license to Chinese players. The Chinese unit is a completely separate entity that has allowed them to circumvent any export restrictions.
Even if somehow SiFive was prevented from licensing to certain Chinese firms, there are several non-US alternatives, even some domestic players. These include Andes, PTG from Alibaba, Syntacore, and Nucleisys. There are also free open-source cores available online.
We have seen that the entity list has the potential to limit ARM’s cooperation with Huawei’s HiSilicon despite it being a UK company owned by Softbank. With RISC-V, such risks are eliminated for Chinese firms. Additionally, it provides a globally recognized open-source standard for the country’s chip designers to latch onto. This removes any trust issues that would undoubtedly arise if China were to push its own closed ISA globally to compete with ARM or Intel.
This year I expect to see several Chinese companies taping out RISC-V based IoT chips as well as AI chips which include the ISA’s cores somewhere in the design. Whilst RISC-V has started with simpler IoT designs or low-power chips like Greenwaves’ GAP8 or the Chinese Kendryte, over the coming years I expect larger, more powerful versions to emerge.
Similar to how ARM boasts a range of cores covering low-power IoT to servers, RISC-V has the potential to do the same. I understand that many RISC-V cores struggle in terms of design size compared with ARM equivalents. However, there is no denying the benefits of this open-source, more customizable ISA that is also more cost-effective. The ecosystem is growing, results are improving, and the competitors are beginning to sweat, even if it is just a little.