The RISC-V Summit is over - here's what you need to know

China's been scammed for billions by rogues in its chase to become a chip powerhouse, but ironically, a free, open-source CPU architecture is emerging as its best bet to create a powerful homegrown chip.

China was a winner at this week's RISC-V Summit, with many organizations introducing CPUs based on RISC-V, an open-source chip architecture sometimes called the Linux of chips. The government-backed Chinese Academy of Sciences, which is on the US Entity List, and StarFive Technology released new RISC-V chip designs for PCs and servers.

The profile of RISC-V is growing with backing from companies including Apple, Intel, Google and Nvidia. But RISC-V development is especially picking up in China, with Alibaba in October opening code of the XuanTie custom-built processors based on RISC-V instruction, and is porting Android 10 to RISC-V ISA.

The country has poured billions into making homegrown chips with the aim of being self-sufficient in the technology. Another goal is to cut the reliance on foreign countries, with chip technology being used as leverage by US in its trade war against China.

For example, the US is limiting chip technology exports to the Chinese Academy of Sciences, which has now turned to RISC-V for CPU development. The organization in 2010 developed the MIPS-based Loongson chip, and the latest chip release earlier this year mixes MIPS with RISC-V. 

RISC-V is attractive to China because it is a borderless architecture, and it isn't controlled by a single company or government entity, Nathan Brookwood, chip analyst at Insight 64, told The Register. Other open-source efforts like OpenPower, which is led by IBM, are concentrated around vendors.

RISC-V provides a chance to break away from the monolithic structure driving the development, production and distribution of chips, and to create a level playing field for smaller chip makers, Brookwood said.

Move fast and break stuff

"We take advantage of the community. We break down corporate barriers, country barriers, cultural barriers, timezone barriers, and we all share that piece because we all know is that we are part of this community," Mark Himelstein, chief technology officer at RISC-V International, told The Register.

The newer Chinese chip designs introduced at RISC-V Summit aren't as advanced as the fastest x86 and ARM CPUs, but the goal is to make a competitive alternative with richer features, if not the latest and greatest.

Chinese Academy of Sciences announced the open-source XiangShan 64-bit chip, called Nanhu, which will tape out next year. The dual-core chip design operates at 2.0GHz, and is close to twice as fast as its single-core predecessor released six months ago based on the 28nm process.

Nanhu is designed for the 14nm process, which means the chip could be made inside China at a fab run by SMIC, which operates at that node. While not as advanced as the cutting-edge 5nm and 4nm nodes run by Taiwan Semiconductor Manufacturing Co., Nanhu does close the manufacturing gap.

It took just 30 people, including 25 graduate students and five engineers, to develop the first RISC-V chip called Yanqihu, said Yungang Bao, professor at Chinese Academy of Sciences' Institute of Computing Technology, during a presentation at the RISC-V Summit in San Francisco. Given the cooperative nature of RISC-V, some of Nanhu's new features draw from SiFive designs like the Block Inclusive Cache.

"For us, we will not launch a startup to commercialize, but we hope there are some other companies to do that," Yungang said, adding "We would like to see a company like Red Hat for RISC-V."

StarFive introduced
Dubhe, a out-of-order mainstream computing chip design, with operates at a frequency of 2GHz when the chip is tuned to Taiwan Semiconductor Manufacturing Co.'s 12nm process.

The chip includes extensions like bit manipulation found in XiangShan but also includes new features like hypervisor, which is in SiFive's P650 RISC-V chip design.

But there are challenges. If Nvidia doesn't acquire ARM - which looks highly unlikely - could be a temporary roadblock in RISC-V's expansion, Brookwood said.

ARM is more like a Switzerland of chip makers with its neutral stance. Companies were ready to bolt ARM if Nvidia took control, and that may slow, Brookwood said. ®

https://www.theregister.com/2021/12/09/china_homegrown_chips/