New RISC-V CPU claims recordbreaking performance per watt

Micro Magic Inc.—a small digital design agency in Sunnyvale, California—has produced a prototype CPU that’s a number of instances extra environment friendly than world-leading opponents, whereas retaining cheap uncooked efficiency.

We first observed Micro Magic’s claims earlier this week, when EE Instances reported on the corporate’s new prototype CPU, which seems to be the quickest RISC-V CPU on the earth. Micro Magic adviser Andy Huang claimed the CPU may produce 13,000 CoreMarks (extra on that later) at 5GHz and 1.1V whereas additionally placing out 11,000 CoreMarks at 4.25GHz—the latter all whereas consuming solely 200mW. Huang demonstrated the CPU—operating on an Odroid board—to EE Instances at 4.327GHz/0.8V and 5.19GHz/1.1V.

Later the identical week, Micro Magic announced the identical CPU may produce over 8,000 CoreMarks at 3GHz whereas consuming solely 69mW of energy.

OK, however what’s a CoreMark?

A part of the problem in evaluating Micro Magic’s declare for its new CPU lies in determining simply what a CoreMark is and what number of of them are wanted to make a quick CPU. It is a intentionally simplified CPU benchmarking instrument launched by the Embedded Microprocessor Benchmark Consortium, supposed to be as platform-neutral and easy to construct and use as potential. CoreMark focuses solely on the core pipeline features of a CPU, together with fundamental learn/write, integer, and management operations. This particularly avoids most results of system variations in reminiscence, I/O, and so forth.

The Embedded Microprocessor Benchmark Consortium (EMBC) is a gaggle with large trade illustration: Intel, Texas Devices, ARM, Realtek, and Nokia are a number of of its extra notable and simply recognizable members.

Now that we understood all that, the following step so as to higher consider Micro Magic’s claims was to run a number of CoreMark benchmarks of our personal. All we wanted to do right here was clone its GitHub repository, then challenge a make command—optionally, with arguments XCFLAGS="-DMULTITHREAD=8 -DUSE_FORK=1" if we wish to take a look at on a number of threads/cores without delay.

I nonetheless have an Apple M1 Mac Mini available, in addition to a Ryzen 7 4700U-powered Acer Swift 3, so these have been my take a look at methods for comparability. Getting the uncooked efficiency scores was significantly simpler than getting really comparable energy readings. On the Ryzen-powered Linux system, I used the utility turbostat to get each Core and Package deal energy readings whereas the checks have been operating.

I haven’t got entry to something almost as fine-grained as turbostat for the Apple M1, so for that platform I took whole-system energy draw on the wall and simply plain subtracted the studying at desktop idle from the sustained studying whereas underneath take a look at. That is extraordinarily crude, and I warning readers to not rely an excessive amount of on evaluating the M1’s effectivity to the Swift 3’s on these numbers alone—but it surely’s ok to get some perspective on Micro Magic’s declare for its new RISC-V (pronounced “danger 5”) CPU.

On to the checks!

The Micro Magic CPU is, for the second, single-core and single-threaded—though Huang says it may “simply” be constructed as a 25-core half. Micro Magic has offered figures—and in a single case, a screenshot—for efficiency at 3GHz, 4.25GHz, and 5GHz. On the maximally power-efficient 3GHz clockrate, the Micro Magic CPU scores about one-fourth the CoreMarks of both the Ryzen 4700u or Apple M1. On the maximally performant 5GHz clock, it manages simply over a 3rd of their efficiency.

This is sufficient to tell us that the Micro Magic chip in its present kind is not a world-class competitor for conventional ARM and x86 CPUs in telephone or laptop computer purposes—but it surely’s a lot nearer to them than earlier RISC-V implementations have been. On the power-efficient 3GHz clockrate, the Micro Magic CPU is sort of 3 times quicker than, for instance, SiFive’s Freedom U540 CPU operating single-threaded. At 5GHz, it outruns all 4 of the SiFive’s cores.

At roughly 1 / 4 the efficiency of world-leading x86 and ARM cell processors, the Micro Magic CPU would not sound like a lot but. However once we think about energy effectivity, issues get loopy. I gave my Ryzen and Apple processors the advantage of each potential doubt when producing the above charts—I used core energy (not whole bundle energy) on the Ryzen 4700U and ran checks with the Gnome3 desktop shut down. For the Apple, I solely had entry to whole-system energy draw, so I subtracted the “desktop idle” energy draw from the “underneath take a look at” energy draw.

I examined the Apple and AMD CPUs each single-threaded and multithreaded when checking energy effectivity. Unsurprisingly, each elements produced extra efficiency per watt when exercised with one work thread for every accessible CPU thread. None of this made a lot of a dent within the Micro Magic’s commanding lead in energy effectivity.

At 4.25GHz, the Micro Magic can accomplish the identical workload because the Ryzen 4700U with lower than one-third the ability required. At 3GHz, that determine plummets to lower than one-eighth the ability required.

What’s it good for?

The Linux working system already helps RISC-V structure—so for headless or near-headless controllers that merely must ship respectable efficiency paired with excessive energy effectivity, Micro Magic’s new CPU is probably going a lot of the manner there. Issues get significantly extra sophisticated when you begin speaking about total consumer-friendly methods, after all. Even other than {hardware} issues like GPU and LTE modem, creating a complete Android telephone based mostly on a non-ARM structure is prone to be a a lot greater enterprise.

With that stated, it is value mentioning that—if we take Micro Magic’s numbers with no consideration—they’re already beating the efficiency of some strong cell phone CPUs. Even at its efficiency-first 3GHz clockrate, the Micro Magic CPU outperformed a Qualcomm Snapdragon 820. The Snapdragon 820 is not world-class anymore, but it surely’s no slouch, both—it was the processor within the US model of Samsung’s Galaxy S7.

If we use the EMBC’s published single-core rating for the Snapdragon 820 together with Anandtech’s single-core CPU energy take a look at result, we get about 16,000 CoreMarks per watt. That is triple the effectivity of the Ryzen 4700u operating single-threaded and a little bit higher than par with it when the Ryzen’s operating an optimally multithreaded workload.

In different phrases, Micro Magic’s prototype CPU is each considerably quicker and tremendously extra power-efficient than a fairly fashionable and nonetheless very succesful smartphone CPU.

Conclusions

All of this sounds very thrilling—Micro Magic’s new prototype is delivering strong smartphone-grade efficiency at a fraction of the ability finances, utilizing an instruction set that Linux already runs natively on. Higher but, the corporate itself is not an unknown.

Micro Magic was initially based in 1995 and was bought by Juniper Networks for $260 million. In 2004, it was reborn underneath its authentic identify by the unique founders—Mark Santoro and Lee Tavrow, who initially labored at Solar and led the workforce that developed the 300MHz SPARC microprocessor.

Micro Magic intends to supply its new RISC-V design to clients utilizing an IP licensing mannequin. The simplicity of the design—RISC-V requires roughly one-tenth the opcodes that fashionable ARM structure does—additional simplifies manufacturing considerations, since RISC-V CPU designs could be inbuilt shuttle runs, sharing area on a wafer with different designs.

With that stated, it could be an unlimited enterprise to port—for instance—a complete smartphone ecosystem, resembling business Android, to a brand new structure. Along with constructing the working system itself—not simply the kernel, however drivers for all {hardware} from GPU to Wi-Fi to LTE modem, and extra—third-party app builders would want to recompile their very own purposes for the brand new structure as effectively.

We’re additionally nonetheless taking a reasonably truthful quantity of Micro Magic’s claims at face worth. Whereas we have seen a screenshot of an 8,200 CoreMark rating, and we have seen a 69mW energy studying, it isn’t solely clear that the ability studying was consultant of all the benchmark run.

Nonetheless, that is an thrilling growth. Not solely does the brand new design seem to carry out effectively whereas massively breaking effectivity data, it is doing so with a much more ideologically open design than its opponents. The RISC-V ISA—in contrast to x86, ARM, and even MIPS—is open and offered underneath royalty-free licenses.