Since the summer of 2010, the Berkeley research team has spent about four years designing and developing a complete new instruction set. This new instruction set is called RISC-V. From its official release in 2014, RISC-V has faced various doubts, but by 2017, the Indian government announced significant funding for RISC-V-based processor projects, making RISC-V the de facto national instruction set of India. This year, domestic policies have also begun to support RISC-V, with Shanghai becoming the first city in China to include RISC-V in government support initiatives. Over 150 companies and research institutions, including IBM, NXP, Western Digital, NVIDIA, Qualcomm, Samsung, Google, Tesla, Huawei, Zhongtian Micro, ZTE Micro, Alibaba, Haoyun, and the Institute of Computing Technology of the Chinese Academy of Sciences, have joined the RISC-V camp.
In just a few years, RISC-V has not only gained policy support but has also attracted increasing attention from enterprises and academia towards this open-source instruction set, even putting pressure on Arm. Since RISC-V’s inception at Berkeley in 2010, the most common sentiment in the industry has been that RISC-V could change the existing competitive landscape dominated by Arm and Intel’s x86 architectures, particularly impacting Arm in the consumer and IoT embedded markets.
Differences Between ARM and RISC-V
Both ARM and RISC-V architectures originate from the Reduced Instruction Set Computer (RISC) of the 1980s. The biggest difference lies in their advocated technical style of simplicity and the completely open model. ARM is a closed instruction set architecture, where many vendors using ARM architecture can only adjust product frequency and power consumption according to their needs without altering the original design. After decades of evolution, the CPU architecture has become extremely complex and cumbersome, with ARM architecture documentation spanning thousands of pages, a complex number of instructions, and numerous versions that are incompatible with each other and do not support modularity, along with high patent and architecture licensing costs. In contrast, RISC-V was designed from the outset as a completely open-source architecture, avoiding the detours of decades of computer architecture development. Its architecture documentation is only over two hundred pages, with basic instructions numbering just over 40, and a single instruction set supports all architectures, allowing users to customize and configure different instruction subsets according to their needs.
What Does the Future Hold for the Competition Between ARM and RISC-V?
Currently, ARM occupies the vast majority of the processor IP market represented by mobile devices, while RISC-V is a rising star. So, what does the future hold?
The competition between ARM and RISC-V is somewhat reminiscent of the Windows vs. Linux battle at the end of the last century, and the future competitive landscape between ARM and RISC-V may be similar. It is almost certain that in ARM’s traditional stronghold, namely the mobile phone sector, RISC-V has little chance, as mobile phones are unlikely to completely change their processor cores after a decade of iteration, much like how Windows remains the dominant operating system in the PC market after over twenty years. However, in emerging fields, RISC-V and ARM are on an equal footing, and RISC-V, with its open-source instruction set and other characteristics, is likely to defeat ARM or at least capture a significant market share. Currently, such emerging markets mainly include the Internet of Things (IoT) market. The IoT market has a long-tail characteristic, with numerous sub-markets and high power consumption requirements, giving RISC-V an advantage due to its ability to flexibly modify instruction sets and chip architecture designs for different applications. In contrast, using ARM often results in a standardized design that is difficult to differentiate. Additionally, the IoT market is cost-sensitive, making RISC-V’s free licensing model important for chip manufacturers. In the RISC-V Foundation’s list, we can see companies like Qualcomm and MediaTek that are heavily investing in the IoT sector. In the currently booming AI chip market, there is no clear advantage for either ARM or RISC-V. This is because, in high-performance AI chips, whether using ARM or RISC-V cores, they are primarily used as controllers, while the most critical computing units are often custom-designed by circuit designers rather than using IP; on the other hand, the profit margins in AI chips are often substantial, so RISC-V’s free characteristics do not provide a significant advantage.
Author: Lang Ruizhike’s Blog