XiangShan – Open-source high performance RISC-V processor

https://github.com/OpenXiangShan/XiangShan

by gjvc • 2 years ago

270 74 2 years ago

fithisux• 2 years ago

Bravo guys! Tremendous piece of work.

paulsutter• 2 years ago

It important to be aware of the significant progress that China is making in AI, robotics, and processors, and admirable that they are open sourcing so much of it.

It’s great work and an inspiration

nine_k2• 2 years ago

Quite possibly the open-sourcing is a part of the success story. The Chinese culture is built around incessant reproducing and gradual improvement, which dates back at least to the times of Confucius. Some think it's mindless copycatting, but it's more about learning deeply and then standing on others' shoulders. It's the "fork this" attitude that meshes quite well with open source, but is understandably infuriating for IP-licensing / patents crowd.

This doesn't mean that the openness extends easily to those outside China, its culture, and especially its language though.

bpfrh• 2 years ago

I don't see that much opensource coming from china.

For example the popular arm rockchip offerings are so bad at contributing to mainline linux or even sharing documentation that the single person supporting them dropped it due to lack of fund and being unable to get any contact to share documentation.

IMHO, chinese opensource does at best the same thing many western companies do:

Opensource the things that are not you secret sauce/income, or things which would benefit you if people adopt them.

With the added caveat that china in generally is notorious for not abiding by patent laws and copying.

Barrin92• 2 years ago

The Chinese culture is built around incessant reproducing and gradual improvement

all successful cultures are, they're just divided on whether they admit it or not. Germany was late to industrialization and a lot of our businesses went to Britain under the pretense of doing business and copied chemical plant factory layouts one-to-one, but we like the "we're the country of engineers and thinkers" story much better than "we were a bit slow and ripped the British and French off".

The Chinese just don't pretend. I've spent a lot of time in China and around FB's attempted Snapchat acquisition in tech circles there used to be the joke that FB is the most Chinese American company because of Zuckerberg's relentless copying. The valley works the exact same way, they're just more likely to pretend everything is the result of some boy genius making it up.

cute_boi• 2 years ago

I hope China don't follow all these IP/patents. They have harmed more imo.

lenerdenator• 2 years ago

Isn't RISC-V FOSS to begin with?

gdiamos• 2 years ago

The instruction set is, not necessarily the implementation.

m3kw9• 2 years ago

What’s the strategy in open sourcing this?

slongfield• 2 years ago

They presented at HotChips 2024: https://www.youtube.com/watch?v=4_R0S6piLA0&t=2114s

There, one of the things they mentioned was that they were hoping that RISC-V in general, and their cores in particular, becomes a platform for academic research. That way, cutting-edge things are shared in the open and the industry benefits globally.

The optimistic view of this is that it's hoping for a better future for all. The cynical view is that open source is much harder to sanction/export control. The truth is probably somewhere in the middle.

blackeyeblitzar• 2 years ago

The strategy is to do PR for China, market for adoption (to break chip duopoly), get contributions (free work), and build momentum to a point where the tech is commoditized (so they can be immune to sanctions).

cookiemonsieur• 2 years ago

then that's a good strategy. It's about time the world takes on western dominance.

szundi• 2 years ago

Other motive could be to undermine western dominance in chip design. You give away free a good enough thing that is competing with your competitor's moat. If the gap is not that significant this can ruin the business for your competitor.

You can see the same with Apple and all big tech funding OpenStreetMap for example vs Google Maps. Even decreasing income for the competitor is worth it strategically. Or Satya Nadella saying in an interview that if ChatGPT just makes Google's costs higher for search is a big win for Microsoft.

whatever1• 2 years ago

Yep. Once espressif gave us the esp32 with 50 cents each we completely forgot about arm etc.

crvdgc• 2 years ago

Realistically, it's probably the group inside the Chinese Academy of Sciences wanting for a larger impact factor for their review, similar to all other state sponsored researching institutes.

jurschreuder• 2 years ago

Universities always make things open source. I also make everything open source that I make for the university.

It's because you cannot make money with it anyway and the university often allows it, so then it's really good for your CV.

In Europe there is also a lot of stuff open source, and I can honestly say there is no plot by the government to destroy the United States. I don't think Linux is a plan by the Swedish government to destroy the USA.

Most Chinese people in my experience also don't really have any country outside of China on their radar, unless they are in some trading business. China is just so huge compared to for example the US, they really live in their own bubble. It's not something they think about on a monthly let alone daily basis is my personal experience.

miki1232113• 2 years ago

And if you want to do a commercial spin-off from your university work, it might be easier to put it all out as MIT/BSD/Apache and then start a completely independent company than to deal with all the paperwork.

This makes life easier for competitors, so it's definitely a tradeoff, but it's the right tradeoff in some circumstances.

usrnm• 2 years ago

I don't think Linux is a plan by the Swedish government to destroy the USA.

Linus comes from a family of ethnic Swedes, but he was born and raised in Finland, the Swedish government had nothing to do with it.

camel-cdr4• 2 years ago

If anyone wants to play arround with simulating it, here is a Dockerfile I use:

    # Dockerfile
    FROM ubuntu:24.04

    RUN apt-get update && apt-get install -y build-essential clang libclang-dev llvm-dev cmake libspdlog-dev vim git curl wget time default-jre default-jdk
    RUN git clone --recursive https://github.com/OpenXiangShan/xs-env
    WORKDIR /xs-env
    RUN sed 's/apt\S* install/\0 -y/g;s/source /. /g;s/sudo //g' -i ./*.sh
    RUN . ./env.sh && sed 's/\/master/\/master/g;s/$/; cd \/xs-env/g' -i ./update-submodule.sh && ./update-submodule.sh


    RUN . ./env.sh && ./setup-tools.sh
    RUN . ./env.sh && . ./install-verilator.sh
    RUN . ./env.sh && sed 's/^git submodule.*$//g;s/env.*$//g' -i ./setup.sh && . ./setup.sh

    RUN . ./env.sh && make -C XiangShan init
    RUN . ./env.sh && cd DRAMsim3 && mkdir build && cd build && cmake -D COSIM=1 .. && make -j 8
    RUN . ./env.sh && make -C XiangShan emu CONFIG=DefaultConfig WITH_DRAMSIM3=1 MFC=1 -j 8

    RUN . ./env.sh \
        && sed 's/unknown-//g;s/rv64gc/rv64gcv/g' -i $AM_HOME/am/arch/*.mk $AM_HOME/am/arch/isa/*.mk \
        && sed 's/define MSTATUS_FS.*$/define MSTATUS_FS 0x6600/g' -i $AM_HOME/am/src/*/isa/riscv/boot/*.S


    WORKDIR nexus-am/apps/hello
    RUN make ARCH=riscv64-xs

    # $NOOP_HOME/build/emu --no-diff -i ./build/hello-riscv64-xs.bin 2>/dev/null

Make sure you have 64GB of RAM. I only had 16GB, but allocating additional 48GB of swap worked.

There are probably some redundant steps, but this worked for me last time I tried.

ge963• 2 years ago

why so much ram?

chrsw4• 2 years ago

64GB of RAM isn't that much for full chip simulation of a "high performance" CPU.

luyu_wu2• 2 years ago

I posted a link to this project a few weeks ago as well! It's really interesting to see an academic project like this one.

For people interested, there's bi-weekly blogs (some in English) linked here: https://docs.xiangshan.cc/zh-cn/latest/blog/

omolobo• 2 years ago

Free hardware is the dream. I want to replace the proprietary, DRM-bloated CPU on my PC yesterday.

luyu_wu2• 2 years ago

Here is a commercial product using the older 'Nanhu' architecture by XiangShan. Doesn't seem to be released yet, but interesting nonetheless!

https://milkv.io/ja/ruyibook

mooreed• 2 years ago

This project is the first that tickles my brain in the right serendipitous ways; it merges topics of my recent interests.

However, after a VERY short perusal, I grew a giant sense of empathy for non-native English speakers. The readme is gentle enough to English speakers (aka: +95% English) no less I felt like I muddled through renaming tokens in my mind as I went. However, that quickly showed me two things.

1. It reminds me why I never seem to finish classic Russian literature… so often get lost in the introductory parade of names that are a cache miss for my usual set of names.

2. This is perhaps a significant cultural muscle that has never been necessitated for English speakers. Since the earth has largely been using English (in some capacity) for significantly longer than my life span - as my favorite joke says in the punch line “what do you call someone who only knows one language… uni-lingual… jk: American”

PS: it seems like there could be an open registry maintained by “Americans like me” who would rather pre-process the code for tokens within the docs and src… seems like a “DefinitelyTyped style” definitions registry would be very niche, but SUPER useful.

musicale2• 2 years ago

as my favorite joke says in the punch line “what do you call someone who only knows one language… uni-lingual… jk: American”

"Another thing to keep in mind, when you get to feeling bad about being monolingual, is that the fair question is not 'how many languages do you know?' It is, 'of the languages spoken by five million people or more within a thousand miles or so of where you live, what percentage do you know?'"

https://structuredprocrastination.com/light/biling.php

notpushkin• 2 years ago

of the languages spoken by five million people or more within a thousand miles or so of where you live, what percentage do you know?

IRL interactions are just one aspect of life. Pretty important, sure, but it’s not the only important thing.

miki1232113• 2 years ago

I prefer to view it as "what's the likelihood that, with your current knowledge of languages, you're able to communicate with any person you may presumably want to speak to in the future."

This is why it's so much easier to only speak English than it is to only speak another language.

fer• 2 years ago

of the languages spoken by five million people or more within a thousand miles or so of where you live, what percentage do you know

By that metric you shouldn't feel bad for not speaking Russian in most of Russia, or for not knowing the most common languages in your immediate surroundings in large swaths of Africa (i.e. most Bantu languages would be excluded).

remexre• 2 years ago

https://github.com/OpenXiangShan/XiangShan-doc/blob/main/doc...

The list of fused instructions is kinda weird; besides the ones that correspond to SH{1,2,3,4}ADD anyway, I don't think I expected any of the others.

I don't see a mention of Sifive-style short jump predication there either, though I'm using Google Translate.

zozbot2342• 2 years ago

Does RISC-V org itself list/document suggested insn fusion sequences anywhere? I can't quite figure out whether they do because the technical wiki they use is quite hard to navigate and search, and their unofficial Github repos are not much better.

snvzz3• 2 years ago

You might find this[0] reddit thread useful.

0. https://old.reddit.com/r/RISCV/comments/1hnm5y1/where_did_th...

Arnavion2• 2 years ago

The ISA spec itself suggests one fusion - that of mul and mulh (lower and upper halves of n-bit * n-bit -> 2n-bit product).

The only other source I know of was this 2016 paper that suggested specific macro fusions. https://arxiv.org/abs/1607.02318 This predates the B extension so some of those fusions are dedicated instructions now, but I suppose Xiangshan still implements them for the sake of software that was not compiled with B enabled.

pantalaimon2• 2 years ago

I wonder what 'high performance' means in that context. So far, RISC-V has been rather underwhelming in regards to performance when compared to ARM or Loongarch (3A6000).

brucehoult2• 2 years ago

That's simply not true. RISC-V cores, SoCs, and boards perform very comparably to even better than Arm devices with similar µarch e.g. SiFive U74 vs Arm A55, SiFive P550 vs Arm A72, THead C906 vs ARM1176.

While Arm CPUs have existed for 40 years, the initial RISC-V spec was frozen and formally published only in mid 2019 and most of the CPUs currently available to buy were designed around that time.

This is quite normal. For example the Arm A76 core that features in the latest Raspberry Pi 5 and RK3588 boards (Rock 5, Orange Pi 5) was announced in May 2018, and took until 2022/3 to be available in consumer SBCs. The A53, A55, and A72 had similar time spans from announcement until being available in SBCs: Pi 3 / Odroid C2; Odroid C4; Pi 4.

Only in November 2024 was a RISC-V ISA spec suitable for high performance phones, laptops, desktops, servers frozen and published: RVA23. Cores meeting this spec and with expected performance comparable to Arm A78 up to maybe X2 have been announced, but it will be several years before they are available in products.

RISC-V is simply very very new. It is doing very well in the markets which it currently addresses.

itomato• 2 years ago

I found these useful:

"The latest version of XiangShan achieves a normalized score of 45 at 3GHz on SPECint 2006. With the performance comparable to ARM Neoverse N2, it is the highest performing open-source processor to our knowledge."

https://riscv-europe.org/summit/2024/media/proceedings/poste...

https://hc2024.hotchips.org/assets/program/conference/day2/2...

snvzz3• 2 years ago

Great, considering the project does not end at V3, and V3 is already competitive.

They will continue to improve the performance.

camel-cdr4• 2 years ago

Check out my comment from a couple of month ago: https://news.ycombinator.com/item?id=41331786#41331968

TLDR in RTL simulation XiangShanV3 out-performs my current desktop (Zen1) per cycle in the tested scalar benchmarks by 2x. It's probably closer to 1.5x on regular code.

This roughly matches the reported SPECint2006 scores:

    * XiangShanV2: 9.55/GHz
    * XiangShanV3: 15/GHz
    * Zen2 [1]: 10.5/GHz at boost, 9/GHz at base frequency (closest to Zen1 I could find)

For comparison:

    * Cortex-X1: 15.73/GHz
    * Apple M1: 21.69/GHz
    * SiFive-P670: >12/GHz
    * SiFive-P870: >18/GHz
    * TT-Ascalon: 18-20/GHz
    * Akeana 5300: 25/GHz

Note that it's hard to find SPECint2006 scores for modern x86 or Arm cores because they all use PECint2017.

The final clock frequency obviously also has a big impact, but XiangShanV3 target 3GHz which is quite decent.

tormeh2• 2 years ago

Cool to see another project using Chisel. Anyone in the industry know what direction things are moving in? Seems like Verilog and VHDL are ripe for disruption. I remember one of them as outright unpleasant from university.

tinco• 2 years ago

What has changed that they are now ripe for disruption? My BSc thesis supervisor runs a company that tries to disrupt Verilog and VHDL and they've been at it for well over a decade. I don't think they're making much of a dent yet but I didn't keep up with the space: https://github.com/clash-lang/clash-compiler. There's also a RISCV implementation written in it.

All the tooling in this space is so expensive to build and expensive to verify, with such a small market that it seems almost impossible for something to ever challenge the incumbent ecosystems in a reasonable span of time.

DriftRegion• 2 years ago

I like that the microarch names -- Yanqihu (雁栖湖), Nanhu (南湖), and Kunminghu (昆明湖) -- are lake-themed. Coffee lake? Skylake? no, Kunming lake.

https://en.m.wikipedia.org/wiki/List_of_Intel_codenames

XiangShan – Open-source high performance RISC-V processor

Related Stories