stay CPU Architecture area ,Arm and X86 They occupy the vast majority of the market share in the mobile end and the desktop end respectively . however , These two giants have very strict authorization control over instruction sets , This means that most chip companies can only buy their semi-finished or nearly finished Technology , On the basis of this, R & D is relatively marginalized , There's no chance to master the real core 、 The underlying technology . A few powerful enterprises can obtain authorization , It costs tens of millions or even hundreds of millions of dollars in licensing fees . This makes
More and more chip R & D enterprises turn to open source RISC-V.
Professor at the University of California, Berkeley 、RISC-V Inventor David Patterson It was a bold prediction ：「
In five to ten years ,RISC-V Probably the most important instruction set in the world 」.
With RISC-V The heat keeps rising , This prediction seems to be coming true .
Some time ago , Reuters and other foreign media reported that ,
Intel Is planning to 20 A hundred million dollars
Acquisition of the world's first company based on RISC-V The semiconductor start-ups of the architecture SiFive. Just last year from
Intel A big quitter in the semiconductor industry
Jim Keller It also revealed that RISC-V The optimism of the future , He said ,「 This is a very good instruction set .（ And Arm and x86 comparison ,） It's the simplest one , Have all the functions you should have , And there's not too much garbage . If I want to build a computer quickly , And hope it runs fast enough , that RISC-V It's the easiest choice .」
Look at the country ,RISC-V And the heat is rising .6 month 21 Japan , The first RISC-V The China summit opened in Shanghai University of science and technology . At this summit , Researcher, Institute of computing technology, Chinese Academy of Sciences 、 China's open order ecology （RISC-V） Secretary General of the League
Baoyungang This paper introduces a new product developed by their team recently
Open source, high performance RISC-V processor —— Xiangshan .
Open source links ：https://github.com/OpenXiangShan/XiangShan （ except GitHub, Several domestic open source platforms Gitee/Trustie/iHub both 「 Xiangshan 」 Mirror image , search 「XiangShan」 You can find .）
Why do it 「 Xiangshan 」？ before , Bao Yungang's team found that ,Linux Be born 30 year , It is not only widely used in industry , It has also become an academic activity
operating system Innovation platform for research , and CPU The field has not yet produced a similar open source mainline .
「 To build a place like Linux Open source like that RISC-V Nuclear mainline , It can be widely used in industry , And support the academic community to experiment with innovative ideas . The key is , Make sure it looks like Linux That way, at least we can survive 30 year .」 This is a 「 Xiangshan 」 Small goals set by the team .
「 We've been preparing for more than a year —— Apply for funds , start-up 『 One heart in one lifetime 』 Plan to train people , Build a team , Looking for partners …… finally , Xiangshan is officially launched .」
It is reported that ,
「 Xiangshan 」 Of
The idea is
Open source code 、 Open process 、 Document disclosure .
It's based on Chisel Hardware design language implementation , Support RV64GC Instruction set . stay 「 Xiangshan 」 In the process of processor development ,
The team used the tools including Chisel、Verilator And so on , The differential verification is realized 、 Simulation snapshot 、RISC-V Checkpoint and other basic tools for processor development , Set up a set of design 、 Realization 、 Agile development process of processor front end based on open source tools, including verification, etc . Its open source license uses the Magnolia relaxed license .
at present ,
「 Xiangshan 」 There are two versions of microarchitecture , The first edition is called 「 Yanqi Lake 」, The second edition is called 「 The south lake 」.
「 Yanqi Lake 」 It's a 11 It's a cascade of water 、6 launch 、4 An out of order processor core with a memory access unit . Its development began with 2020 year 6 month ,RTL This year 4 Month completion . The frequency of the architecture can reach
The performance is expected to reach 7 branch / GHz（SPEC CPU 2006）.
「 Yanqi Lake 」 Architecture Overview .
stay RISC-V At the China Summit , Bao Yungang introduced 「 Yanqi Lake 」 Several key decisions in architecture development .
The first decision is to choose
Use Chisel Language （ An open source hardware building language released by the University of Berkeley ）. With the use of traditional Verilog Language comparison , Use Chisel The efficiency of agile development can be improved 13 times , The amount of code is only that of traditional development 1/5, And it can reach the quality level of traditional development .
The second decision is
Focus on building processes and tools to support agile design , Including efficiency close to QEMU High performance interpreter based on NEMU、TL-C Uniformity Cache Software testing framework for Agent Faker、 Instruction level online differential verification framework Difftest、 Memory based lightweight simulation snapshot LightSSS、 A debug stack to bridge the gap between low-level waveform and high-level semantics Waveform Terminator、 Can be in 10 It's estimated in an hour that RISC-V CPU SPEC The score of BetaPoint etc. . These tools speed up the entire development and validation process .
Bao Yungang said ,「 Yanqi Lake 」 Will be in
7 In the middle of the month , The goal for the future is to achieve
ARM Cortex-A76 The level of performance .
And 「 Yanqi Lake 」 comparison ,「 The south lake 」 The goal of design is higher ：
The frequency is expected to reach 2GHz@SMIC 14nm, The performance is expected to reach 10 branch / GHz（SPEC CPU 2006 ）. This version was designed this year 3 Month start , expect 2021 The end of the year .
By 2021 year 6 month 1 Japan , share 25 A classmate from the Institute of computing, Chinese Academy of Sciences / Teachers participate in 「 Xiangshan 」 project , They contributed 31784 Xingxiangshan nuclear design code and 18317 Line validation framework code .
Down payment 「 One heart in one lifetime 」 Five students in the program （ Jin Yue 、 Wang Huaqiang 、 Wang Kaifan 、 Zhang Linjun 、 Zhang Zifei ） As soon as I graduated, I joined the development of Xiangshan , Become the backbone of Technology .6 month 19 Japan , The technical team held a seminar in Nanhu, Jiaxing .
Bao Yungang said , To build something like Linux Such an open source platform for architecture innovation widely used in industry , Make Xiangshan survive 30 In the target . So , They still have a lot of work to do , Including maintaining the iterative optimization frequency of the half year update generation architecture ; Every year, 2 Secondary film , For the new architecture 、 New function verification, etc .
Cooperation , Beijing micronucleus core technology is 「 Xiangshan 」 The first phase industrial experience is provided 、 Help to complete the structural design and physical design . at present , The second phase of the project is recruiting joint development partners , Companies that have joined include micronucleus cores 、
Bytes to beat 、 Beijing yisiwei 、 Yousi technology, etc . Bao Yungang said ,「 The positive feedback from industry , Let's practice it more firmly
Research heavy industry mode .」（ The mode of scientific research and heavy industry is keen on developing prototype systems that can really change the status quo , Even if it takes a lot of Engineering , The typical representative is the University of California, Berkeley .）
from 「 Xiangshan 」 It's not hard to see that , The domestic semiconductor industry is very interested in RISC-V And the enthusiasm for it continues to rise . But there's no denying it , It's going to take a while for the ecosystem of this instruction set to build . In an interview some time ago , Bao Yungang said frankly that , use RISC-V The application of requirements in complex scenarios is still in its infancy , If you want to go into a server with rich and stable Ecology 、 The computer 、 Traditional areas such as mobile phones , There is still a long way to go . He estimated roughly that , At the very least 5 - 10 year .
Some people think that , Because it's open enough ,RISC-V In the future, our ecological weakness may turn into an advantage .「 The ecological environment of industry is still forming , There's no old overlord , We have the opportunity to build instruction sets 、 Core chip 、
operating system , And the upper application 、 Controllable ecology including cloud services .」
Hua Mei Technology Founder Huang Wang said .
Of course , Ecological construction is not an easy thing .「 about RISC-V Come on , It's a challenge to get the players involved to work together .」
Alibaba Gao Hui, head of pingtouge's marketing department, pointed out that , In the past ARM and X86 These command sets all have a core player , Push the instruction set to evolve in a certain direction . Now? , Open source RISC-V Attracted a lot of players , We need to think about how to form a joint force , Instead of branching out .
Actually , This is also 「 Xiangshan 」 One of the original purposes of the project , namely 「 formation 『 Cooperation before competition 』, Realize the joint development and open source of all walks of life CPU framework 」. Only by strengthening cooperation ,RISC-V Only in this way can ecology develop and grow as soon as possible .