8 ms·

RVVM – The RISC-V Virtual Machine

140 points by api 4y ago

xiphias2 4y ago
[flagged]
- lib-dev 4y ago
  What icon?
  - codetrotter 4y ago
    He’s talking about the cigarette emoji
  - flyaway123 4y ago
    Updated: https://github.com/LekKit/RVVM/commit/a36af6823acdd75e9d966cf19482d86df388d347 https://github.com/LekKit/RVVM/commit/a36af6823acdd75e9d966c...
    - bheadmaster 4y ago
      I hate lightbulbs... I have light sensitivity and it makes me hurt literally, and it destroys the ecosystem. Please take out that icon :(
    - xiphias2 4y ago
      Thanks
- bheadmaster 4y ago
  Do icons of cigarettes make you sick and destroy millions of lives? Does removing an icon of cigarette make you less sick and help save millions of lives?
  - api 4y ago
    That comment is actually a good politically-neutral illustration of a major force underpinning today's political hyper-polarization: people simply can't handle the mere existence of something they don't like and will respond by shunning entire bodies of work or attacking people unnecessarily. This is definitely new as in the last 10-15 years. In the past more people seemed able to just disregard or shrug at things they didn't approve of. We've had eras of profound intolerance before. I think this one might be unique in that it seems universal across the entire political and social spectrum.
    - Joker_vD 4y ago
      Reminds me of [0]. The original poster's account is deleted, but it was "@Christian-Schiffer" — yes, the person who complained about presence of a Christmas-related icon in VS Code had name "Christian". And the VS Code team responded immediately, the icon was removed what, one or two days after the complaint, in an urgently published patch. [0] https://github.com/microsoft/vscode/issues/87268 https://github.com/microsoft/vscode/issues/87268
    - thebooktocome 4y ago
      Have you heard of the Vatican’s Index Librorum Prohibitorum? This isn’t exactly a new phenomenon.
    - pjmlp 4y ago
      Having been raised out of a dictorship I don't have any patience for the cancelation culture that is now so trendy. If those people would get visits from PIDE/DGS, or similar agencies, they would see how real cancelation actually works in practice.
      - bheadmaster 4y ago
        I agree. I think that people who haven't been raised in such a society don't realize how chilling it is to be afraid to say something wrong and constantly be aware that you could be punished for your words. It makes you unable to even think clearly, lest a slip-of-tongue gets you sent to jail. It's no way to live.
ognyankulev 4y ago
Instruction interpreter is nicely human-readable: https://github.com/LekKit/RVVM/blob/staging/src/cpu/riscv_i.c https://github.com/LekKit/RVVM/blob/staging/src/cpu/riscv_i....
- bippingchip 4y ago
  The RISC-V isa is specifically designed to be nice and regular and easy to decode, and work with, which definitely shows here (also in the RTL code if you look at some of the well designed RISC-V cores) Of course, bot x86 and Arm started like that as well - but after 20+ years of evolution, they have to drag along a lot of history. (and one never really takes things away from an ISA, you only add new features, and at best deprecate old ones). That said, with the extensibility of the ISA in mind as a design principle, I do have good hopes, RISC-V will stand the test of time reasonable well in that sense...
  - klelatti 4y ago
    The ARM64 ISA does not have 20+ years of evolution as it was announced in 2011. It’s essentially a brand new ISA and has cast off almost all of the legacy of previous Arm ISAs.
    - firstlink 4y ago
      This seems right at first; however, about half of the armv8 spec is taken up by a copy of the armv7 spec and info about interop between the two ISAs. So armv8 isa is considerably constrained not only by the interop requirements, whereby an armv8 OS/hypervisor must be able to control the environment of an armv7 process/OS, but also by the need for implementing both ISAs without excessive duplication of silicon. For example, an actual v8+v7 implementation must surely have a single pipeline supporting both ISAs.
      - klelatti 4y ago
        I think the key test is whether significant features that were seen as problematic in earlier versions have indeed survived. AFAIK almost all were fixed. Patterson and Henessy comment as to how different (better) ARM64 is when compared to previous versions!
synergy20 4y ago
How is this different from QEMU which also supports RISC-V 32|64 fairly well.
- bippingchip 4y ago
  I had the exact same question. I do like this - it's nice and ambitious to build something like this from the ground up. Looking at the todo list though, they still have quite some work to get to parity with qemu...
  - LekKit 4y ago
    See my nearby post on this thread, hope it'll explain stuff
- api 4y ago
  It's supposed to be faster, smaller, and easier to integrate into other applications and systems than QEMU. In my tests it's sometimes faster and definitely smaller and simpler. I think it's also easier to build as WASM and run in a browser. I don't think 100% feature parity with QEMU is a goal.
- LekKit 4y ago
  Basically there are few design choices where it's substantially different to QEMU. Performance-wise: - Instead of a static translate-and-run flow like in QEMU, RVVM has an interpret-trace-run execution loop which is remotely similar to JVM, and allows to collect some data like branch probabilities and hot loops, and optimize better - Using a hardware host FPU instead of softfp emulation. This is like, 10x faster with some synthetic FPU benchmarks - Conscious decisions for beneficial trade-offs, like fast-path JIT trace cache, JIT IR is more streamlined to "Big ISA Triad" (RISC-V, ARM64, x86-64), etc Infrastructure-wise: - A public library API for a lot of things: Machine management (Construct and run 'em in any program), device integration, registering new CPU instructions, userspace emulation - Subjectively, a more lean and clean codebase, in places where it wasn't harmed by either 1) performance decisions to copy-paste or restructure things 2) complexity of related things like JIT backend arches - Portability. RVVM officially runs in WASM, runs on Haiku, SerenityOS, KolibriOS, even DOS! So yeah, while I can't say for sure it's the fastest RISC-V VM, but if we had a bunch more contributors and a bit more popularity it could definitely take a part of the QEMU crown (For things like distro building and god knows what else). There are a few other differences here & there, but they aren't as much worth mentioning. Do you believe I should make some kind of QEMU/RVVM comparison anywhere in the repo? It seems kind of selfish to present it like that...
dist1ll 4y ago
You're not allowed to use branding material of the RISC-V foundation to advertise your personal project. I suggest removing the logo to avoid your repo being taken down.
- doe88 4y ago
  Indeed, until reading your comment, I thought it was official. At least a short disclaimer would be welcome.
- api 4y ago
  Should probably create an issue for this. I'd have never imagined this so I'm sure the author doesn't know.
- punnerud 4y ago
  An issue and discussion of if now: https://github.com/LekKit/RVVM/issues/77 https://github.com/LekKit/RVVM/issues/77 This is not commercial and the terms for the logo is: “(..) The RISC-V trade mark or the RISC-V logo may be freely used for non-commercial research and academic projects as long as the guidelines below are followed. Individual members may not use the RISC-V trademark for commercial purposes (..)” So they will probably not remove it.
  - snvzz 4y ago
    I think guidelines-wise the use is fine, except "The RISC-V..." is toiling the line vs "A RISC-V...".
efficax 4y ago
are there any risc v sbcs out there that are actually available? every one i look for is out of stock. i’d love to play around with a real chip
- t-3 4y ago
  Starfive Visionfive 2 looks to be in stock on Ameridroid and Kickstarter? Pine's Ox64 says it will restock "in March". Last I checked, Clockwork Pi was also selling their RISCV modules separately for ~$20. If you're willing to play with RV32, there are quite a few MCU boards available - CH32V003, BL602, ESP32, etc. Many ARM SBCs also have a RISCV MCU built in, but I haven't seen any docs or reports of anyone actually using the "mailbox" mechanism to run code on it. If nothing else works, get a cheap FPGA and run a softcore?
- snvzz 4y ago
  VisionFive 2 is the fastest money can buy while also being under $100, making it about the automatic choice today.
  - brucehoult 4y ago
    Right now, yes. Sipeed LP4A (and other TH1520 boards) should be close to 2x the speed, certainly if run with cooling to permit the rated 2.5 GHz speed, in April or May maybe. For around $100. And the SiFive "HiFive Pro" maybe 1.5x faster again in late summer, though probably quite a bit more expensive.
icelake111 4y ago
[dead]

140 points by api 4y ago

xiphias2 4y ago

[flagged]

lib-dev 4y ago
What icon?
- codetrotter 4y ago
  He’s talking about the cigarette emoji
- flyaway123 4y ago
  Updated: https://github.com/LekKit/RVVM/commit/a36af6823acdd75e9d966cf19482d86df388d347 https://github.com/LekKit/RVVM/commit/a36af6823acdd75e9d966c...
  - bheadmaster 4y ago
    I hate lightbulbs... I have light sensitivity and it makes me hurt literally, and it destroys the ecosystem. Please take out that icon :(
  - xiphias2 4y ago
    Thanks
bheadmaster 4y ago
Do icons of cigarettes make you sick and destroy millions of lives? Does removing an icon of cigarette make you less sick and help save millions of lives?
- api 4y ago
  That comment is actually a good politically-neutral illustration of a major force underpinning today's political hyper-polarization: people simply can't handle the mere existence of something they don't like and will respond by shunning entire bodies of work or attacking people unnecessarily. This is definitely new as in the last 10-15 years. In the past more people seemed able to just disregard or shrug at things they didn't approve of. We've had eras of profound intolerance before. I think this one might be unique in that it seems universal across the entire political and social spectrum.
  - Joker_vD 4y ago
    Reminds me of [0]. The original poster's account is deleted, but it was "@Christian-Schiffer" — yes, the person who complained about presence of a Christmas-related icon in VS Code had name "Christian". And the VS Code team responded immediately, the icon was removed what, one or two days after the complaint, in an urgently published patch. [0] https://github.com/microsoft/vscode/issues/87268 https://github.com/microsoft/vscode/issues/87268
  - thebooktocome 4y ago
    Have you heard of the Vatican’s Index Librorum Prohibitorum? This isn’t exactly a new phenomenon.
  - pjmlp 4y ago
    Having been raised out of a dictorship I don't have any patience for the cancelation culture that is now so trendy. If those people would get visits from PIDE/DGS, or similar agencies, they would see how real cancelation actually works in practice.
    - bheadmaster 4y ago
      I agree. I think that people who haven't been raised in such a society don't realize how chilling it is to be afraid to say something wrong and constantly be aware that you could be punished for your words. It makes you unable to even think clearly, lest a slip-of-tongue gets you sent to jail. It's no way to live.

ognyankulev 4y ago

Instruction interpreter is nicely human-readable: https://github.com/LekKit/RVVM/blob/staging/src/cpu/riscv_i.c https://github.com/LekKit/RVVM/blob/staging/src/cpu/riscv_i....

bippingchip 4y ago
The RISC-V isa is specifically designed to be nice and regular and easy to decode, and work with, which definitely shows here (also in the RTL code if you look at some of the well designed RISC-V cores) Of course, bot x86 and Arm started like that as well - but after 20+ years of evolution, they have to drag along a lot of history. (and one never really takes things away from an ISA, you only add new features, and at best deprecate old ones). That said, with the extensibility of the ISA in mind as a design principle, I do have good hopes, RISC-V will stand the test of time reasonable well in that sense...
- klelatti 4y ago
  The ARM64 ISA does not have 20+ years of evolution as it was announced in 2011. It’s essentially a brand new ISA and has cast off almost all of the legacy of previous Arm ISAs.
  - firstlink 4y ago
    This seems right at first; however, about half of the armv8 spec is taken up by a copy of the armv7 spec and info about interop between the two ISAs. So armv8 isa is considerably constrained not only by the interop requirements, whereby an armv8 OS/hypervisor must be able to control the environment of an armv7 process/OS, but also by the need for implementing both ISAs without excessive duplication of silicon. For example, an actual v8+v7 implementation must surely have a single pipeline supporting both ISAs.
    - klelatti 4y ago
      I think the key test is whether significant features that were seen as problematic in earlier versions have indeed survived. AFAIK almost all were fixed. Patterson and Henessy comment as to how different (better) ARM64 is when compared to previous versions!

synergy20 4y ago

How is this different from QEMU which also supports RISC-V 32|64 fairly well.

bippingchip 4y ago
I had the exact same question. I do like this - it's nice and ambitious to build something like this from the ground up. Looking at the todo list though, they still have quite some work to get to parity with qemu...
- LekKit 4y ago
  See my nearby post on this thread, hope it'll explain stuff
api 4y ago
It's supposed to be faster, smaller, and easier to integrate into other applications and systems than QEMU. In my tests it's sometimes faster and definitely smaller and simpler. I think it's also easier to build as WASM and run in a browser. I don't think 100% feature parity with QEMU is a goal.
LekKit 4y ago
Basically there are few design choices where it's substantially different to QEMU. Performance-wise: - Instead of a static translate-and-run flow like in QEMU, RVVM has an interpret-trace-run execution loop which is remotely similar to JVM, and allows to collect some data like branch probabilities and hot loops, and optimize better - Using a hardware host FPU instead of softfp emulation. This is like, 10x faster with some synthetic FPU benchmarks - Conscious decisions for beneficial trade-offs, like fast-path JIT trace cache, JIT IR is more streamlined to "Big ISA Triad" (RISC-V, ARM64, x86-64), etc Infrastructure-wise: - A public library API for a lot of things: Machine management (Construct and run 'em in any program), device integration, registering new CPU instructions, userspace emulation - Subjectively, a more lean and clean codebase, in places where it wasn't harmed by either 1) performance decisions to copy-paste or restructure things 2) complexity of related things like JIT backend arches - Portability. RVVM officially runs in WASM, runs on Haiku, SerenityOS, KolibriOS, even DOS! So yeah, while I can't say for sure it's the fastest RISC-V VM, but if we had a bunch more contributors and a bit more popularity it could definitely take a part of the QEMU crown (For things like distro building and god knows what else). There are a few other differences here & there, but they aren't as much worth mentioning. Do you believe I should make some kind of QEMU/RVVM comparison anywhere in the repo? It seems kind of selfish to present it like that...

dist1ll 4y ago

You're not allowed to use branding material of the RISC-V foundation to advertise your personal project. I suggest removing the logo to avoid your repo being taken down.

doe88 4y ago
Indeed, until reading your comment, I thought it was official. At least a short disclaimer would be welcome.
api 4y ago
Should probably create an issue for this. I'd have never imagined this so I'm sure the author doesn't know.
punnerud 4y ago
An issue and discussion of if now: https://github.com/LekKit/RVVM/issues/77 https://github.com/LekKit/RVVM/issues/77 This is not commercial and the terms for the logo is: “(..) The RISC-V trade mark or the RISC-V logo may be freely used for non-commercial research and academic projects as long as the guidelines below are followed. Individual members may not use the RISC-V trademark for commercial purposes (..)” So they will probably not remove it.
- snvzz 4y ago
  I think guidelines-wise the use is fine, except "The RISC-V..." is toiling the line vs "A RISC-V...".

efficax 4y ago

are there any risc v sbcs out there that are actually available? every one i look for is out of stock. i’d love to play around with a real chip

t-3 4y ago
Starfive Visionfive 2 looks to be in stock on Ameridroid and Kickstarter? Pine's Ox64 says it will restock "in March". Last I checked, Clockwork Pi was also selling their RISCV modules separately for ~$20. If you're willing to play with RV32, there are quite a few MCU boards available - CH32V003, BL602, ESP32, etc. Many ARM SBCs also have a RISCV MCU built in, but I haven't seen any docs or reports of anyone actually using the "mailbox" mechanism to run code on it. If nothing else works, get a cheap FPGA and run a softcore?
snvzz 4y ago
VisionFive 2 is the fastest money can buy while also being under $100, making it about the automatic choice today.
- brucehoult 4y ago
  Right now, yes. Sipeed LP4A (and other TH1520 boards) should be close to 2x the speed, certainly if run with cooling to permit the rated 2.5 GHz speed, in April or May maybe. For around $100. And the SiFive "HiFive Pro" maybe 1.5x faster again in late summer, though probably quite a bit more expensive.

icelake111 4y ago

[dead]