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BeagleV – An affordable RISC-V computer designed to run Linux

beaglev.seeed.cc

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Re: BeagleV – An affordable RISC-V computer designed to run Linux

#91

Post by qwerty456127 »

mrweasel wrote: post #53

Is there something inherently complicated in adding a SATA/M.2 port to board like this? The RaspberryPi is also "disk-less", which to me is one of the major limitations. It's a super interesting little board, and I love that it's a RISC-V, that could really help getting the CPU in the hands of people. I just don't know enough about these things to understand why there are no storage connectors (other than an SD card…

Why would you need SATA when you have SD, also USB3 and Gigabit Ethernet? I have no problem booting from the SD then accessing data on my SATA drives using a USB-attached controller, also plan to get a NAS.

Sure, it would be great to have connectors for everything and support for every cool standard but these guys have to give up all what is non-essential to keep it small, cheap and possible to engineer by a small team.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#92

Post by hajile »

IshKebab wrote: post #56
alkonaut wrote: post #40

Can someone explain the technical benefits of this architecture over the competition? That is should I be excited if I don't care about e.g. openness? Or is it simply an effort to create something that is a half-decent cpu alternative but open? Is there anything about RISC-V that is "better" simply because it is a later design than others? Is it likely to evolve faster because it is open or more modern?

Compared to ARM, nothing significant. They're very similar load-store architectures. Here's a RISC-V quick reference: https://www.cl.cam.ac.uk/teaching/1617/ECAD+Arch/files/docs/... And ARM: http://users.ece.utexas.edu/~valvano/Volume1/QuickReferenceC... The main difference is that RISC-V is a lot more modular, so it's going to be difficult to distribute binaries for but more flexible if you're doing something comple…

> The main difference is that RISC-V is a lot more modular, so it's going to be difficult to distribute binaries for but more flexible if you're doing something completely vertical. Also a lot of the modules have bundle relatively common/easy instructions with niche/difficult ones. E.g. multiply with divide.

I don't think it'll be worse than ARM and it's decidedly better than x86.

There are SEVEN major revisions of ARMv8. Then there's v8-R, v8-M, and additional 32-bit variants of each instruction set in addition to both ARMv7 and ARMv6 which also still ship billions of chips per year. Oh, and under pressure from companies, ARM also allows custom instructions now. Those aren't just theoretical either -- Apple at least added a ton of custom matrix instructions to the M1.

For x86, supporting only semi-recent processors (2006 Core or greater) leaves you still checking for support for: SSE3, SSE4, SSE4.1, SSE4a, SSE4.2, SSE5, AVX, AVX2, AVX512, XOP, AES, SHA, TBM, ABM, BMI1, BMI2, F16C, ADX, CLMUL, FMA3, FMA4, LWP, SMX, TSX, RdRand, MPX, SGX, SME, and TME. That's 29 instruction sets and not all of them have use on both Intel and AMD chips.

RISC-V seems at least that cohesive. If you're shipping a general purpose CPU, you'll always have mul/div, compression, fusion (not actually instructions), privilege, single precision, double precision, bit manipulation, and probably a few others.

Where you'll run into mul/div missing or no floats are microcontrollers or "Larabee" style GPU cores. In all of those cases, you'll be coding to a very specific core, so that won't really matter.

Thankfully, we've had ways to specify and/or check these kinds of things for decades.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#93

Post by drewm1980 »

ansible wrote: post #52
alkonaut wrote: post #40

Can someone explain the technical benefits of this architecture over the competition? That is should I be excited if I don't care about e.g. openness? Or is it simply an effort to create something that is a half-decent cpu alternative but open? Is there anything about RISC-V that is "better" simply because it is a later design than others? Is it likely to evolve faster because it is open or more modern?

> Is there anything about RISC-V that is "better" simply because it is a later design than others? A lot of it is because it is newer, and the designers have learned from previous architectures. It is a relatively clean and straightforward instruction set, designed to be easily and efficiently implemented. There's not anything that is super crazy revolutionary, in contrast to the (still vaporware) Mill CPU architectu…

The mill has been in development for... 18 ~years now! Soon they will be able to hire engineers who are actually younger than the company. I wonder if there has ever been a tech company that survived so long without bringing a product to market. Duke Nukem Forever took ~14 years.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#94

Post by mrweasel »

brucehoult wrote: post #90
mrweasel wrote: post #53

Is there something inherently complicated in adding a SATA/M.2 port to board like this? The RaspberryPi is also "disk-less", which to me is one of the major limitations. It's a super interesting little board, and I love that it's a RISC-V, that could really help getting the CPU in the hands of people. I just don't know enough about these things to understand why there are no storage connectors (other than an SD card…

https://www.crowdsupply.com/sifive/hifive-unmatched PCIe, 16 GB DDR4, two M.2 (one for storage, one WIFI), quad core 1.5 GHz (same cores as this board, but twice as many)

That's a little costly, but I guess development of a board like that isn't cheap.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#95

Post by numpad0 »

mrweasel wrote: post #53

Is there something inherently complicated in adding a SATA/M.2 port to board like this? The RaspberryPi is also "disk-less", which to me is one of the major limitations. It's a super interesting little board, and I love that it's a RISC-V, that could really help getting the CPU in the hands of people. I just don't know enough about these things to understand why there are no storage connectors (other than an SD card…

Yes; SATA host controller is an extra if the SoC don't come with one, connectors can't be cheap either. Too expensive as a nice-to-have item.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#96

Post by Drdrdrq »

cjbconnor wrote: post #69
lsb wrote: post #63

Earlier quoted context omitted.

You can get an SD card with 0.5TB capacity on it for USD$30, what storage needs do you foresee? Also these tend to be used where weight is an issue, so, why do you want to lug around a huge disk?

Nearly all SD cards that I've used in Pis and other SBCs have died unpredictably in the past, so I've pretty much given up on using them

Same here. I now run them read only.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#97

Post by brucehoult »

IshKebab wrote: post #56
alkonaut wrote: post #40

Can someone explain the technical benefits of this architecture over the competition? That is should I be excited if I don't care about e.g. openness? Or is it simply an effort to create something that is a half-decent cpu alternative but open? Is there anything about RISC-V that is "better" simply because it is a later design than others? Is it likely to evolve faster because it is open or more modern?

Compared to ARM, nothing significant. They're very similar load-store architectures. Here's a RISC-V quick reference: https://www.cl.cam.ac.uk/teaching/1617/ECAD+Arch/files/docs/... And ARM: http://users.ece.utexas.edu/~valvano/Volume1/QuickReferenceC... The main difference is that RISC-V is a lot more modular, so it's going to be difficult to distribute binaries for but more flexible if you're doing something comple…

If you're doing something embedded nothing prevents you implementing multiply but not divide. RISC-V gcc has an option to use an instruction for multiply but runtime library call for divide.

In fact, even if you claim to implement the M extension (both multiply and divide) all that is necessary is that programs using those opcode work -- but that can be via trap and emulate. If your overall system can run binaries with multiply and divide instructions in them then you can claim M-extension. Whether the performance is adequate is between you and your customers. Note that there are also vast differences in performance between different hardware implementations of multiply and divide, with 32-64 cycle latencies not unheard of.

The same applies for implementing a subset of other extensions in hardware. You can implement the uncommon ones in the trap handler if that will meet your customer's performance needs.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#98

Post by brucehoult »

hajile wrote: post #92
IshKebab wrote: post #56

Earlier quoted context omitted.

Compared to ARM, nothing significant. They're very similar load-store architectures. Here's a RISC-V quick reference: https://www.cl.cam.ac.uk/teaching/1617/ECAD+Arch/files/docs/... And ARM: http://users.ece.utexas.edu/~valvano/Volume1/QuickReferenceC... The main difference is that RISC-V is a lot more modular, so it's going to be difficult to distribute binaries for but more flexible if you're doing something comple…

> The main difference is that RISC-V is a lot more modular, so it's going to be difficult to distribute binaries for but more flexible if you're doing something completely vertical. Also a lot of the modules have bundle relatively common/easy instructions with niche/difficult ones. E.g. multiply with divide. I don't think it'll be worse than ARM and it's decidedly better than x86. There are SEVEN major revisions of A…

Do you have a reason to think the matrix instructions in the M1 are not those specified in Armv8.6-A?

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#99

Post by brucehoult »

karakanb wrote: post #8

The website is super slow. It downloads 7.66MB of files, and it took 1.05min to load for me on a 2020 MBP with 150Mbps bandwidth and ~15ms latency.

I didn't measure the size, but it loaded in 4 seconds here in Chrome on Ubuntu, via VDSL.

Re: BeagleV – An affordable RISC-V computer designed to run Linux

#100

Post by brucehoult »

mrweasel wrote: post #94
brucehoult wrote: post #90

Earlier quoted context omitted.

https://www.crowdsupply.com/sifive/hifive-unmatched PCIe, 16 GB DDR4, two M.2 (one for storage, one WIFI), quad core 1.5 GHz (same cores as this board, but twice as many)

That's a little costly, but I guess development of a board like that isn't cheap.

Existing is the first step. Prices will reduce in time -- probably quite rapidly.
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