Building Faster Processors with RISC-Five

By Hubert Yoshida posted 04-21-2021 04:16

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The miniaturization of semiconductor transistors has driven the growth in computer performance for more than 50 years. As miniaturization approaches its limits, bringing an end to Moore’s law, performance gains will need to come from software, algorithms, hardware and the need to move from general purpose to specialized processors.

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New applications like Deep Learning and autonomous vehicles are demanding even faster processors while mobile devices and IoT require lower power consumption as well as increased performance. One of the major changes has been the movement to RISC processors made by
ARM (Advanced RISC Machines). RISC processors are designed to perform a smaller number of types of computer instructions so that they can operate at a higher speed, performing more millions of instructions per second (MIPS). By stripping out unneeded instructions and optimizing pathways, RISC processors provide outstanding performance at a fraction of the power demand of CISC (complex instruction set computing) devices.

The Intel x86 is a CISC processor where the instructions available are more focused on performing complex tasks with large amounts of flexibility. Common operations include multiplication with floating point numbers, complex memory manipulation, memory searches, and much more. 99+% of laptops, desktops, and servers run on x86. However they do consume more power to do these complex operations.

Last year Apple made waves by deciding to drop the x86 which they have been using in their laptops and desktops since 2005. Apple is now making their own Mac chips based on the RISC ISA which they license from ARM. Apple already uses their own chips in their iPhones and iPads. Apple builds the chips, Apple makes the software, and Apple designs the hardware — every part of the process is under Apple’s control. Now, Apple is potentially poised to bring those same benefits to its Macs.

Apple claims that their new 13.3-inch MacBook Air based on its eight-core M1 chip, surpasses the previous x86 model with a huge performance leap in both central processing and graphics processing. Apple claims 3.5-times greater speed than the Intel CPU and the integrated GPU offers five-times the performance of Intel Iris Plus graphics. Apple also claims that the system is energy efficient and can provide up to 18 hours of battery life on a single charge. The lower power means this new model has no fan. The M1 chip is Arm based.

While these performance and energy claims are outstanding, there is a new innovation which may prove to be even more outstanding. While x86 and Arm are the predominate ISAs, they are proprietary. A decade ago David Patterson, who is already well known for his work on RAID at U.C. Berkeley, co-created an ISA, an open standard chip instructions, known as RISC-V, pronounced RSIC – five. The purpose was to create a lingua franca for
computer chips, a set of instructions that could be used by all chipmakers and
owned by none. It wasn't supposed to be an impressive new technology, it was merely supposed to get the industry on the same page, to simplify chip-making in order to move
things forward. However, the open approach has begun to produce some stunning breakthroughs.

Micro Magic Inc., a Silicon Valley intellectual property designer for chips that has been consulting to all the big Valley firms for twenty-five years has demonstrated ultra low power 64-bit RISC-V core with a clock speed of 5 gigahertz, consuming only 10mW at 1Ghz.

As a comparison, a clock speed of 5 gigahertz is well above a recent, top-of-the-line Intel Xeon server chip, E7, running at 3.2 gigahertz. Even more amazing is that the novel RISC-V chip burns just 1 watt of power at 1.1 volts, less than one percent of the power burned by the Intel Xeon.
The speed and power efficiency of the RISC-V part also tops the specs for Exynos 4, a top-of-
the line part made by Samsung Electronics for its smartphones, based on the computing
core provided by ARM Holdings Plc, Intel's chief rival.

David Patterson, in an interview with ZDNet, describing his impression of a demo he was given of the chip recently said "I think IBM mainframes have a 5-gigahertz product that's liquid-cooled, and takes 100 watts" to run.

While Open source has been available for software for some time, the same has not been true for the processor chips. You have to pay for the proprietary hardware licenses for x86 or ARM. RISC-Five is a new architecture that changes the game and is available under open, free and non-restrictive licenses. It has widespread industry support from chip and device makers and is designed to be freely extensible and customizable to fit any market niche. This open source approach is sparking the competition which will drive the next generation of processors.

RISC-Five gets its name from the fifth RISC architecture to come from U. C. Berkeley. The RISC-V Foundation has more than 200 members, including Samsung, Google, Nvidia, Western Digital, NXP, Micron, Hitachi, and Qualcomm, not to mention Raspberry Pi.
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