Stories
Slash Boxes
Comments

SoylentNews is people

posted by Fnord666 on Thursday October 31 2019, @02:06AM   Printer-friendly
from the processing-in-a-disorderly-manner dept.

SiFive Announces First RISC-V OoO CPU Core: The U8-Series Processor IP

In the last few year's we've seen an increasing amount of talk about RISC-V and it becoming real competitor to the Arm in the embedded market. Indeed, we've seen a lot of vendors make the switch from licensing Arm's architecture and IP designs to the open-source RISC-V architecture and either licensed or custom-made IP based on the ISA. While many vendors do choose to design their own microarchitectures to replace Arm-based microcontroller designs in their products, things get a little bit more complicated once you scale up in performance. It's here where SiFive comes into play as a RISC-V IP vendor offering more complex designs for companies to license – essentially a similar business model to Arm's – just that it's based on the new open ISA.

Today's announcement marks a milestone in SiFive's IP offering as the company is revealing its first ever out-of-order CPU microarchitecture, promising a significant performance jump over existing RISC-V cores, and offering competitive PPA metrics compared to Arm's products. [...] SiFive's design goals for the U8-Series are quite straightforward: Compared to an Arm Cortex-A72, the U8-Series aims to be comparable in performance, while offering 1.5x better power efficiency at the same time as using half the area. The A72 is quite an old comparison point by now, however SiFive's PPA targets are comparatively quite high, meaning the U8 should be quite competitive to Arm's latest generation cores.

Performance gains over previous designs are substantial:

The performance increases compared to previous generation SiFive cores are extremely impressive: Against a U54 at ISO-process, the new U84 features a 5.3x performance increase in SPECint2006. When taking into account the process node improvements that allow the U84 to clock higher, the generational increases that we'd be seeing in products will be more akin to a factor of 7.2x.

In terms of PPA, compared to a U7-series CPU, IPC increases come in at 2.3x resulting in 3.1x higher performance (ISO-process). A lot of the performance increases of the U8-series come thanks to the increased frequencies capabilities which are 1.4x higher this generation, with the core scaling up to 2.6GHz on 7nm.

On the same 7nm process, the U84 lands in at 0.28mm² per core and a cluster comprising four cores and a 2MB L2 cache measure in at 2.63mm². For comparison, an Arm Cortex-A55 as measured on the Kirin 980, also on 7nm, a core with its 128KB private L2 cache comes in at 0.36mm². Given that SiFive promises of similar performance to a Cortex-A72, which in turn would be more than double the performance of an A55, it looks like SiFive's U84 core would be extremely competitive in terms of its PPA.

Related: Qualcomm Invests in RISC-V Startup SiFive


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by RamiK on Thursday October 31 2019, @05:06PM (6 children)

    by RamiK (1813) on Thursday October 31 2019, @05:06PM (#914233)

    They get what takes the other fabless 5years done under 3 or even 2 years and with a small team. And they deliver with an open source compiler... Mighty impressive.

    --
    compiling...
    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 1, Insightful) by Anonymous Coward on Thursday October 31 2019, @06:45PM (4 children)

    by Anonymous Coward on Thursday October 31 2019, @06:45PM (#914277)

    we need open designs, not licensed designs. change your usurious business model.

    • (Score: 2) by DannyB on Thursday October 31 2019, @08:26PM

      by DannyB (5839) Subscriber Badge on Thursday October 31 2019, @08:26PM (#914315) Journal

      I agree.

      It's the same old argument and history playing out but in hardware.

      fanboy: "But Windows isn't that expensive, in fact it's include on the PC and subsidized by the included malware. It's great!"

      But I believed even in 2000 that open source would win. Trying to stop it is like trying to stop the incoming tide on the beach by using your hands. Or trying to prevent the sun from shining by holding your hands up in the sky to cover the sun. The force of open grows and in time becomes overwhelming. But proprietary sure did beat it for marketing, short term penetration, and a seeming gloss of skin deep quality. But here we are today and Linux and other open source powers everything. Microsoft is trying to embrace it all as fast as they can.

      It will be the same with hardware. Some closed designs. But I think open is what will ultimately win. I would simply ask what was it that motivated the entire RISC-V design and effort in the first place? Those motives are still in play. And more and more users will realize how those open motives benefit them in a tangible way, while the addictive sweetness of proprietary is like a drug dealer's first hit for free.

      --
      People today are educated enough to repeat what they are taught but not to question what they are taught.
    • (Score: 2) by RamiK on Thursday October 31 2019, @09:33PM (2 children)

      by RamiK (1813) on Thursday October 31 2019, @09:33PM (#914345)

      we need open designs, not licensed designs.

      Not me. The purpose of free open software is to prevent vendor locks from the hardware side to the developer's side and from the developer's side to the end-customer. The purpose of a free and open ISA is to prevent vendor lock from the hardware side to the developer's side. What's the purpose of a free and open design? The fabs can't become a natural monopoly due to geopolitical competition preventing any one country from charging too much. The fabless can't become a natural monopoly thanks to the market demanding the use of free and open ISAs especially from the compiler and kernel people.

      Even from a security standpoint they're useless since we have no way to validate what they're actually manufacturing.

      So no. We don't need open designs. It would be nice for society's progress if the different parties could collaborate instead of compete. But it's also a good space for some competition.

      That being said, for smaller cores the design should be open. There's nothing to improve in those spaces so it's just wasting everyone's resources to have competing designs at the micro-controller space.

      --
      compiling...
      • (Score: 0) by Anonymous Coward on Saturday November 02 2019, @06:26PM (1 child)

        by Anonymous Coward on Saturday November 02 2019, @06:26PM (#915071)

        "What's the purpose of a free and open design?"

        there's a lot i don't know about hardware design and manufacturing, but in the future i want people to be able to print a board from a spec file at home or buy parts like this via a distributed ledger type app that orders one from some person who designed their own and prints in their garage or small town coop or something. i'm sick of big companies controlling everything. i'm not concerned about whether one country's huge company can grow beyond it's borders. i want power for the individual.

        • (Score: 2) by RamiK on Saturday November 02 2019, @08:30PM

          by RamiK (1813) on Saturday November 02 2019, @08:30PM (#915111)

          You might get decent enough PCB desktop printers soon that print out commercial grade boards. Maybe they'll even do SMT placing to some extent for some very odd repair service jobs. But short of magic grade technological leaps, the individual components are always going to be sourced from factories and will always cost dozens of times more to purchase individually than in bulk.

          Look, I love Emerson and transcendentalism as much as the next guy, but this whole self-reliance dream been done to death as far back as Brook Farm [wikipedia.org].

          Only empowerment individual get in modern society is through making sure there's competition on the supply's side. Open design when you need a whole industrial chain to produce those designs is about as open as give the Windows source code to the Amish.

          --
          compiling...
  • (Score: 2) by driverless on Sunday November 03 2019, @02:33AM

    by driverless (4770) on Sunday November 03 2019, @02:33AM (#915189)

    They're crazy good at manipulating figures. Look up what PPA means. It wouldn't surprise me if a 6502 (built with current tech, not 1970s hand-laid-out rubylith) had better PPA figures than a SiFive CPU.