Open source POWER ISA takes aim at Intel and Arm for accelerator-driven computing

Third-party hardware firms can now integrate the POWER ISA into their own products, making the architecture effectively the high-performance computing counterpart to RISC-V.

Why OpenPOWER's royalty-free ISA is set to transform enterprise compute Now, the POWER ISA can be integrated, royalty-free, making the architecture the high-performance counterpart to RISC-V. IBM is publishing reference implementations to help companies get started.

IBM announced the release of the POWER instruction set architecture (ISA) as an open standard at the OpenPOWER Summit in San Diego on Tuesday. This announcement comes six years after the formation of the OpenPOWER Foundation, which aimed to foster the creation of hardware from third-party vendors that integrates the POWER architecture in the datacenter. 

While the POWER ISA was itself licensable following the creation of the OpenPOWER Foundation in 2013, that came at a cost. Now, the POWER ISA is available royalty-free, inclusive of patent rights. IBM is releasing a soft core reference implementation of the POWER ISA, and reference designs for Open Coherent Accelerator Processor Interface (OpenCAPI) and Open Memory Interface (OMI) architecture-agnostic compute accelerators. 

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As part of a proof-of-concept, a Xilinx FPGA running the soft core reference POWER implementation is on display at the Summit. "We started the project as a case study to see how hard would it be, to go from a blank sheet of paper and build a core off our [reference implementation]," Mendy Furmanek, president of the OpenPOWER Foundation, told TechRepublic. "It was done very quickly, over a matter of months of part time research."

OpenPOWER management moving under the Linux Foundation

As part of this initiative, the OpenPOWER Foundation is becoming a unit of the Linux Foundation, adopting its governance rules in the migration. While there have been a number of cases where open source technology is "donated" to community organizations following the end of principal development, Ken King, general manager of OpenPOWER for IBM, is quick to push back at the notion that this move signals an end-of-the-line for POWER.

"It doesn't slow down one bit—this is to drive incremental industry innovation. We continue to innovate with the ISA itself, and that's the one unique capability of the governance [model] that we are adding from normal OpenPOWER," King told TechRepublic. "We can update the ISA without needing the vote of the community—and that's a reinforcement of the necessity we have with our architecture, to continue to grow it. We are investing in the future of POWER immensely, and aggressively as we ever have. We're giving the community the ability to be able to also do that with the majority vote, where we only get one vote." King also added that "We still know that we are the centerpiece of POWER itself, and we need to continue to be able to innovate as we need to grow the POWER Architecture to support all of our future products on it."

How RISC-V and OpenPOWER will coexist

The Linux Foundation is well-equipped to take on the OpenPOWER Foundation, given its work with the RISC-V Foundation in promoting adoption of that open-source ISA, which is targeted toward embedded and edge use cases. While initiatives such as the Hi-Five Unleashed that can run Linux, the two ISAs generally target different use cases.

"RISC-V is complimentary—it's not a comparative situation, [it] raises the overall technical commons," OpenPOWER Foundation executive director Hugh Blemings told TechRepublic. "All around, RISC-V has its own strengths and simplicity, as does OpenPOWER."

Likewise, Furmanek stated that "I definitely would want to join together, on how we grow with the hardware ecosystem. When you design chips, you need a lot of tools and verification environments [that] we want to push to have open. That's where a space where we can collaborate a lot, to try to—together—get the Open Hardware movement to go faster."

Will an open POWER ISA deflate ARM prospects in the datacenter?

Prospects of ARM-powered CPUs gaining mainstream acceptance in the datacenter have, to date, been undercut by AMD's targeting of Intel in the enterprise computing market, providing a compelling cost/performance ratio to Intel, while retaining the x86-64 architecture eliminates the porting and optimizing required of an alternative ISA, such as ARM or POWER. 

Performance improvements in AMD EPYC processors are upending Intel's hegemonic grip on the datacenter. With that orthodoxy already challenged, the potential for an alternative ISA to gain a substantial foothold for next-generation, accelerator-driven computing does exist, with representatives from OpenPOWER emphasizing POWER9's position at the center of Summit and Sierra, which lead the Top 500 list of the most powerful supercomputers.

While Fujitsu is leaning on ARM for their Post-K supercomputer, momentum for ARM in the datacenter is not likely to be aided by a royalty-free POWER ISA. Qualcomm's exit from the ARM-powered server market in 2018 has already lowered expectations, with Microsoft's promises of Windows Server on ARM evaporating. Huawei's Kunpeng 920 CPU is unlikely to make any impact outside of China (and the unsettled nature of the US trade dispute threatens Huawei's access to the ARM ISA). As it is, Amazon is the only major public cloud vendor offering ARM servers at present, with on-premises hardware calling on the shoulders of Cavium—now Marvell—which is expected to announce ThunderX3 later this year.

For more, check out "Raptor's Talos II Lite brings POWER9 to the desktop without breaking the bank" and "Linus Torvalds praises Arm servers, but claims the economics and ecosystem are missing" on TechRepublic.

Disclosure: James Sanders is an Associate member of the OpenPOWER Foundation.

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A POWER9 CPU.

Image: IBM