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SiFive Details New Performance P650 RISC-V Core

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  • Alexmitter
    replied
    Originally posted by microcode View Post

    That's not really accurate. The cores are actually marketed to SoC integrators, and they've set up a whole thing to help integrators get to fab. None of the SiFive cores previously mass produced were high performance, but they are in mass market products already. This core could easily fit into mass market products.
    The cores are. Not the Chips SiFive makes themself, again SiFive is a design house making license core designs.
    Of course could this core fit in a mass market product, no doubt. But it won't be SiFive who makes the Chip. Its gonna be Allwinner, or StarFive, or T-Head or any other actual SoC maker.

    Leave a comment:


  • Alexmitter
    replied
    Originally posted by marios View Post

    It is not so impressive. It would be more impressive if it was mature.
    At least from sifive, there is no performant board yet (remember all released boards have an in-order cpu, which means poor performance).
    There are still lots of low hanging fruits to grab (OoO, prefetchers, branch predictors, etc.). When they run out of low hanging fruits, the progress in performance will be way slower.

    tl;dr: It is easier to get faster when you are slow...
    Keep in mind that those in order CPU cores already compete with OoO ARM Cores with all the fancy bells and whistles, and that at a significantly smaller footprint.
    A main issue with the current FU chips is rather the low clock speed they have.

    I can really not complain about the speed of my HiFive Unmatched, the only really painful thing about it is that so many things use Rust now but rust depends on the terrible joke called LLVM and that simply does not work right at all currently. So, no Firefox, not even smaller things with rust in it.

    Leave a comment:


  • kgardas
    replied
    Intel is stepping into the water and they plan to create horse creek dev. platform with p550 and with their other IP (dram/pcie). IIRC this is planned for '22: https://www.sifive.com/press/sifive-...ard-as-highest
    https://www.anandtech.com/show/16780...on-7nm-in-2022

    Mentioned process is Intel 7nm which IIRC was before Intel renamed them so it should be Intel 4 now. Correct me if I'm wrong here. Basically speaking Intel will test Intel 4 production with producing fastest sifive cores (which are really small) and make that advertisement for their foundry services and help risc-v movement and a little bit put sand to arm machine...

    Leave a comment:


  • bob l'eponge
    replied
    There's https://github.com/vortexgpgpu/vortex for the GPU part (although, right now, it's mainly focused on OpenCL, a Vulkan compatible implementation is still far away).

    As for the vector extension, you are wrong. There are vector extension in the RISC V instruction set. Unlike x86 and ARM8, the vector size is dynamic (there is no 128bits version, then 256 bits then 512 bits and so one). The CPU implementation actually dispatch the vectorized instruction as much as it's able to (so yes, there can be a 23 simultaneous operation per iterations in RISC V if the CPU has support for such number). This presents multiple advantages:
    1. You don't need to rewrite your SIMD code when a new version of the CPU/architecture is out
    2. The same code will always performs as fast as possible on RISC-V

    The cons are less obvious:
    1. You don't have as many vectorized instructions as a x86 CPU, so your pipeline might be struck by a non vectorized complex mask instruction for example.
    2. You can't port your NEON, AVX, SSE2 assembly by just finding a 1:1 match in the right instruction. You have to rethink the algorithm à-la OpenMP way.

    Leave a comment:


  • marios
    replied
    Originally posted by tildearrow View Post
    The progress of RISC-V performance seems to be very... fast.
    Impressive considering the architecture isn't that old.
    It is not so impressive. It would be more impressive if it was mature.
    At least from sifive, there is no performant board yet (remember all released boards have an in-order cpu, which means poor performance).
    There are still lots of low hanging fruits to grab (OoO, prefetchers, branch predictors, etc.). When they run out of low hanging fruits, the progress in performance will be way slower.

    tl;dr: It is easier to get faster when you are slow...

    Leave a comment:


  • PerformanceExpert
    replied
    Originally posted by tildearrow View Post
    The progress of RISC-V performance seems to be very... fast.
    Impressive considering the architecture isn't that old.
    Let's ignore that it doesn't have a vector extension which would make any comparison with Cortex-A77 highly speculative. But what I'd like to know is whether anyone has proof of any OoO core from SiFive that has made it into silicon or even better, an actual product?

    So far the progress you're talking about exists on powerpoint slides only.

    Leave a comment:


  • microcode
    replied
    Originally posted by Alexmitter View Post
    SiFive is not a SoC manufacturer, they are a design house and their cores are example implementations of the instruction set. All their SoC products are tech demos and are not made for the mass market.
    That's not really accurate. The cores are actually marketed to SoC integrators, and they've set up a whole thing to help integrators get to fab. None of the SiFive cores previously mass produced were high performance, but they are in mass market products already. This core could easily fit into mass market products.

    Leave a comment:


  • CTown
    replied
    Originally posted by mbello View Post
    SiFive should partner with Raspberry Pi foundation to have its cores on all coming RPi boards. Putting millions of cheap RISC V boards in the hands of tinkerers is a good way for architecture to gain widespread software support.
    Support is always a vague term, it is not only about whether it works, but how solid/reliable it is, whether key software pieces have been optimized for it, etc.
    All that depends on having a large user community.
    That would be very interesting, as that will give them scale to lower prices. Still, what GPU would be used in that case?

    Leave a comment:


  • tildearrow
    replied
    The progress of RISC-V performance seems to be very... fast.
    Impressive considering the architecture isn't that old.

    Leave a comment:


  • Alexmitter
    replied
    Originally posted by mbello View Post
    SiFive should partner with Raspberry Pi foundation to have its cores on all coming RPi boards. Putting millions of cheap RISC V boards in the hands of tinkerers is a good way for architecture to gain widespread software support.
    Support is always a vague term, it is not only about whether it works, but how solid/reliable it is, whether key software pieces have been optimized for it, etc.
    All that depends on having a large user community.
    SiFive is not a SoC manufacturer, they are a design house and their cores are example implementations of the instruction set. All their SoC products are tech demos and are not made for the mass market.

    Leave a comment:

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