XiangShan open-source 64-bit RISC-V processor to rival Arm Cortex-A76
cnx-software.com
cnx-software.com
The headline is getting slightly ahead of the actual performance. Reaching Cortex-A76 performance is their goal after many more iterations. Their current implementation is not there yet, but that shouldn't detract from the magnitude of their achievement and their contribution to the open-source world:
> This culminated with an 8-core prototype built based on Yanqihu (雁栖湖) architecture using TSMC’s 28nm process with the processor running up to 1.2 or 1.3 GHz that should be taped out this month. But plans have been made to tape out a new prototype based on Nanhu (南湖) by the end of the year, using SMIC’s 14nm process allowing up to 2 GHz frequency, and further iterations of the architecture will aim at rivaling Arm’s Cortex-A76 processor.
RISC-V is an exciting development in the SoC world. We're starting to see some of HiFive's boards trickle out into the wild. The performance is good, but it's not quite as groundbreaking as many of the headlines make it out to be. The most exciting part of all of this is that ARM has more competition and we get to see some open-source contributions like this.
Afaict, most of the ARM ugliness was around non-"CPU" SoC components. But it definitely seemed like kernel code organization wasn't ready for a 10x (or 100x) explosion of popular SoCs.
And the entire point of open sourced RISC-V cores is that they would enable even more chip diversity, no?
1) Qualcomm and other SoC vendors fighting interoperability
and
2) Users not understanding device tree.
Unfortunately, the licensing model does require the implementations to be FLOSS. This encourages creating a lot of closed stuff with different and incompatible extensions.
Vendors are free to use custom extensions to implement the bootloader and SBI. Normal code and even the OS won't see that. They can also use custom extensions in hardware drivers. Even in libc, if they want, though that gives more maintenance work.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...
Compare this to the ARM tree there are a few more:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...
Source: https://github.com/esmil/linux/pull/6#issuecomment-844135991
I'm forgetting the source, but some book I read discussed some period of silicon valley as a place where colleges quite routinely exposed students to chip-making. It sounded like the fabs of the area greatly supported these efforts. I'm not sure where I read it but it's stuck with me across many years, always strongly affirming my belief that people, when given exposure to how & means to do, begin many great things.
The main problem is there are only so many universities with so many sections therefore quite a lot of students don't get exposure, even within a given EE department. And even if they could offer it to all students, many wouldn't enroll, as you're basically doing this class constantly for like a year, for not that many credits relative to the time spent, as it sucks down just tons of hours as one gets familiar with all the nitpicky details that one needs to know. And as one learns to deal with the joy that is CAD tooling.
However, in my opinion, the experience in invaluable. And students that can pass that course, with a successful chip in hand, are hand picked by employers. We sure do.
EE272 at Stanford actually started to post their flow. Another benefit of the open source PDKs.
https://code.stanford.edu/ee272/skywater-digital-flow
There are actually many interesting student designs out there. For example this OoO RV64GC RISC-V core from Berkeley: https://chipyard.readthedocs.io/en/latest/Generators/BOOM.ht...
You can find a more detailed write-up of that course and other courses it inspired (as well as some of the practical challenges involved) in her retrospective in IEEE Solid-State Circuits Magazine [2].
An excerpt:
> "Importantly, these weren’t just any designs, for many pushed the envelope of system architecture. Jim Clark, for instance, prototyped the Geometry Engine and went on to launch Silicon Graphics Incorporated based on that work (see Fig. 16). Guy Steele, Gerry Sussman, Jack Holloway and Alan Bell created the follow-on ‘Scheme’ (a dialect of LISP) microprocessor, another stunning design."
[1] https://ai.eecs.umich.edu/people/conway/VLSI/MIT78/MIT78.htm...
雁栖湖 → yangqi lake 南湖 → south lake
There will be many more stories about Chinese "Open Source" CPUs, because the USA has declared a strategy for this decade to control and limit the flow of advanced semiconductor tech to China. China would love to have bright minds from the West contribute to "Chinese Open Source" CPUs. Western contributors will find that these "Open Source" designs can only be economically fabricated in China, though, creating dependence on China.
They are getting perf-per-watt numbers that are ahead of everyone...albeit with a single core and no real 3rd party verification.
Some of the group had worked on Sparc at Sun, and they had previously sold themselves to Juniper for $260M, then regrouped some time afterwards.
Obviously I would love those perf-per-watt numbers to be correct, but it doesn't seem like they have shown it yet.
It seems like their design workflow is ahead of the rest of the field.
Unfortunately most of the licenses used are not reciprocal and this does not encourage building ecosystems.
So it seems like there already is a little bit of an ecosystem.
So at least they're aware of the problem, although that doesn't guarantee that they'll fare better in terms of attracting outside contributions.
Quite the opposite. Requiring most people in the world to learn a second and a third language to access science, technology and international job markets creates a higher barrier and increases inequality.
Amount is for uncountable nouns, like butter, sugar etc.
That's actually not true. More people speak Mandarin as a first language than English (which is third, behind Spanish as well). However, far more people speak English as a second (or third) language than do as a first language, so that English is actually the most widely spoken language.
English is popular as second language just because english is at the present moment the language with more access to documentation and resources, so more people needed to learn it to defeat language barriers. If in the future the language with more resources became Mandarin, more people will learn it as a second language.
2) Even if they were as equally distributed, you'd still be wrong about the number of speakers.
I feel this has been already happening with ARM.
Perhaps also a testament to what you get in terms of productivity, if you use a more modern platform / language (Chisel/Scala).
Productivity goes from design to client satisfaction :) A very productive team is not a team who prints an open source document nobody can use !
Which apparently grants a patent license.
It's a great small hike you should do if you visit the city. Start the hike around 4.30pm to catch the sunset. https://taiwangoldcard.com/images/taiwan-unsplash.jpeg
Personally, it would be great if names on western websites are written with logograms in parenthesis and names on Chinese websites are written with spelled characters in parenthesis. Just another one of those weird cross-cultural areas of friction.