About the Project
The supercomputer Fugaku development plan initiated by the Ministry of
Education, Culture, Sports, Science and Technology in 2014, has set the goal
to develop: (1) the next generation flagship supercomputer of Japan (the
successor to the K computer); and (2) a wide range of applications that will
address social and scientific issues of high priority.
RIKEN Center for Computational Science (R-CCS) has been appointed to lead
the development of Fugaku with the aim to start public service in FY2021. We
are committed to develop a world-leading, versatile supercomputer and its
applications, building on the research, technologies, and experience
obtained through the use of the K computer.
The MEXT, R-CCS and its corporate partner will collaborate with several
research institutions and universities to co-design the system and
applications in order to address the high priority social and scientific
issues identified by the MEXT.
Outline of the Development of the Supercomputer Fugaku
The supercomputer Fugaku will be developed based on the following guiding
principles:
Top priority on problem-solving research
During development, highest priority will be given to creating a system
capable of contributing to the solution of various scientific and societal
issues. For this, the hardware and software will be developed in a
coordinated way (Co-design), with the aim to make it usable in a variety of
fields.
World-leading performance
Create the most advanced general-use system in the world.
Improve performance through international cooperation
While leveraging Japan’s strengths, cooperate internationally to achieve
world-leading technologies of the highest quality and become the
international standard.
Continue the legacy of the K computer
Make the fullest use of the technologies, human resources, and applications
of the K computer project for developing the Fugaku system.
Japan’s Fugaku gains title as world’s fastest supercomputer
The supercomputer Fugaku, which is being developed jointly by RIKEN and
Fujitsu Limited based on Arm® technology, has taken the top spot on the
Top500 listThe webpage will open in a new tab., a ranking of the world’s
fastest supercomputers. It also swept the other rankings of supercomputer
performance, taking first place on the HPCGThe webpage will open in a new
tab., a ranking of supercomputers running real-world applications, HPL-AIThe
webpage will open in a new tab., which ranks supercomputers based on their
performance capabilities for tasks typically used in artificial intelligence
applications, and Graph 500The webpage will open in a new tab., which ranks
systems based on data-intensive loads. This is the first time in history
that the same supercomputer has become No.1 on Top500, HPCG, and Graph500
simultaneously. The awards were announced on June 22 at the ISC High
Performance 2020 DigitalThe webpage will open in a new tab., an
international high-performance computing conference.
On the Top500, it achieved a LINPACK score of 415.53 petaflops, a much
higher score than the 148.6 petaflops of its nearest competitor, Summit in
the United States, using 152,064 of its eventual 158,976 nodes. This marks
the first time a Japanese system has taken the top ranking since June 2011,
when the K computer—Fugaku’s predecessor—took first place. On HPCG, it
scored 13,400 teraflops using 138,240 nodes, and on HPL-AI it gained a score
of 1.421 exaflops—the first time a computer has even earned an exascale
rating on any list—using 126,720 nodes.
The top ranking on Graph 500 was won by a collaboration involving RIKEN,
Kyushu University, Fixstars Corporation, and Fujitsu Limited. Using 92,160
nodes, it solved a breadth-first search of an enormous graph with 1.1
trillion nodes and 17.6 trillion edges in approximately 0.25 seconds,
earning it a score of 70,980 gigaTEPS, more than doubling the score of
31,303 gigaTEPS the K computer and far surpassing China’s Sunway TaihuLight,
which is currently second on the list, with 23,756 gigaTEPS.
Fugaku, which is currently installed at the RIKEN Center for Computational
Science (R-CCS) in Kobe, Japan, is being developed under a national plan to
design Japan’s next generation flagship supercomputer and to carry out a
wide range of applications that will address high-priority social and
scientific issues. It will be put to use in applications aimed at achieving
the Society 5.0 planThe webpage will open in a new tab., by running
applications in areas such as drug discovery; personalized and preventive
medicine; simulations of natural disasters; weather and climate forecasting;
energy creation, storage, and use; development of clean energy; new material
development; new design and production processes; and—as a purely scientific
endeavor—elucidation of the fundamental laws and evolution of the universe.
In addition, Fugaku is currently being used on an experimental basis for
research on COVID-19, including on diagnostics, therapeutics, and
simulations of the spread of the virus. The new supercomputer is scheduled
to begin full operation in fiscal 2021 (which starts in April 2021).
According to Satoshi Matsuoka, director of RIKEN R-CCS, “Ten years after the
initial concept was proposed, and six years after the official start of the
project, Fugaku is now near completion. Fugaku was developed based on the
idea of achieving high performance on a variety of applications of great
public interest, such as the achievement of Society 5.0, and we are very
happy that it has shown itself to be outstanding on all the major
supercomputer benchmarks. In addition to its use as a supercomputer, I hope
that the leading-edge IT developed for it will contribute to major advances
on difficult social challenges such as COVID-19.”
According to Naoki Shinjo, Corporate Executive Officer of Fujitsu Limited,
“I believe that our decision to use a co-design process for Fugaku, which
involved working with RIKEN and other parties to create the system, was a
key to our winning the top position on a number of rankings. I am
particularly proud that we were able to do this just one month after the
delivery of the system was finished, even during the COVID-19 crisis. I
would like to express our sincere gratitude to RIKEN and all the other
parties for their generous cooperation and support. I very much hope that
Fugaku will show itself to be highly effective in real-world applications
and will help to realize Society 5.0.”
“The supercomputer Fugaku illustrates a dramatic shift in the type of
compute that has been traditionally used in these powerful machines, and it
is proof of the innovation that can happen with flexible computing solutions
driven by a strong ecosystem,” said Rene Haas, President, IPG, Arm. “For
Arm, this achievement showcases the power efficiency, performance and
scalability of our compute platform, which spans from smartphones to the
world’s fastest supercomputer. We congratulate RIKEN and Fujitsu Limited for
challenging the status quo and showing the world what is possible in
Arm-based high-performance computing.”
The most important thing you need to understand about the role Arm processor
architecture plays in any computing or communications market — smartphones,
personal computers, servers, or otherwise — is this: Arm Holdings, Ltd.,
which is based in Cambridge, UK, designs the components of processors for
others to build. Arm owns these designs, along with the architecture of
their instruction sets, such as 64-bit ARM64. Its business model is to
license the intellectual property (IP) for these components and the
instruction set to other companies, enabling them to build systems around
them that incorporate their own designs as well as Arm's. For its customers
who build systems around these chips, Arm has done the hard part for them.
Arm Holdings, Ltd. does not manufacture its own chips. It has no fabrication
facilities of its own. Instead, it licenses these rights to other companies,
which Arm Holdings calls "partners." They utilize Arm's architectural model
as a kind of template, building systems that use Arm cores as their central
processors.
These Arm partners are allowed to design the rest of their own systems,
perhaps manufacture those systems -- or outsource their production to others
-- and then sell them as their own. Many Samsung and Apple smartphones and
tablets, and essentially all devices produced by Qualcomm, utilize some Arm
intellectual property. A new wave of servers produced with Arm-based
systems-on-a-chip (SoC) has already made headway in competing against x86,
especially with low-power or special-use models. Each device incorporating
an Arm processor tends to be its own unique system, like the multi-part
Qualcomm Snapdragon 845 mobile processor depicted above. (Qualcomm announced
its 865 Plus 5G mobile platform in early July.)
Last August, Arm announced it had signed a partnership agreement with the US
Defense Dept.'s DARPA agency, giving Pentagon research teams access to Arm's
technology portfolio for research purposes.
Arm processors: Everything you need to know
WHAT WILL NVIDIA'S ROLE BE IN OPERATING ARM?
On September 13, Nvidia announced a deal to acquire Arm Holdings , Ltd. from
its parent company, Tokyo-based Softbank Group Corp., in a cash and stock
exchange valued at $40 billion. The deal is pending regulatory review in the
European Union, United States, Japan, and China, in separate processes that
could take as long as 18 months to conclude.
In a September 14 press conference, Nvidia CEO Jensen Huang told reporters
his intention is to maintain Arm's current business model, without
influencing its current mix of partners. However, Huang also stated his
intention to "add" access to Nvidia's GPU technology to Arm's portfolio of
IP offered to partners, giving Arm licensees access to Nvidia designs.
What's unclear at the time the deal was announced is what a prospective
partner would want with a GPU design, besides the opportunity to compete
against Nvidia.
Arm designs are created with the intention of being mixed-and-matched in
various configurations, depending on the unique needs of its partners. The
Arm Foundry program is a partnership between Arm Holdings and fabricators of
semiconductors, such as Taiwan-based TSMC and US-based Intel, giving
licensees multiple options for producing systems that incorporate Arm
technology. (Prior to the September announcement, when Arm was
considered for sale, rumored potential buyers included TSMC and
Samsung.) By comparison, Nvidia produces exclusive GPU designs, with
the intention of being exclusively produced at a foundry of its choosing —
originally IBM, then largely TSMC, and most recently Samsung. Nvidia's
designs are expressly intended for these particular foundries — for
instance, to take advantage of Samsung's Extreme Ultra-Violet (EUV)
lithography process.
Arm processors: Everything you need to know
After a colossal $40 billion deal with GPU maker Nvidia closes in 2021 or
early 2022, there’s a good chance Arm’s intellectual property may be part of
every widely distributed processor that is not x86.
HOW IS ARM DIFFERENT FROM X86 CPUS OR NVIDIA GPUS?
An x86-based PC or server is built to some common set of specifications for
performance and compatibility. Such a PC isn't so much designed as
assembled. This keeps costs low for hardware vendors, but it also relegates
most of the innovation and feature-level premiums to software, and perhaps a
few nuances of implementation. The x86 device ecosystem is populated by
interchangeable parts, at least insofar as architecture is concerned
(granted, AMD and Intel processors have not been socket-compatible for quite
some time).
The Arm ecosystem is populated by some of the same components, such as
memory, storage, and interfaces, but otherwise by complete systems designed
and optimized for the components they utilize.
This does not necessarily give Arm devices, appliances, or servers any
automatic advantage over Intel and AMD. Intel and x86 have been dominant in
the computing processor space for the better part of four decades, and Arm
chips have existed in one form or another for nearly all of that time --
since 1985. Its entire history has been about finding success in markets
that x86 technology had not fully exploited or in which x86 was showing
weakness, or in markets where x86 simply cannot be adapted.
For tablet computers, more recently in data center servers, and soon once
again in desktop and laptop computers, the vendor of an Arm-based device or
system is no longer relegated to being simply an assembler of parts. This
makes any direct, unit-to-unit comparison of Arm vs. x86 processor
components somewhat frivolous, as a device or system based on one could
easily and consistently outperform the other, based on how that system was
designed, assembled, and even packaged.
The class of processor now known as GPU originated as a graphics
co-processor for PCs, and is still prominently used for that purpose.
However, largely due to the influence of Nvidia in the artificial
intelligence space, the GPU has come to be regarded as one class of
general-purpose accelerator, as well as a principal computing component in
supercomputers — being coupled with, rather than subordinate to,
supercomputers. The GPU's strong suit is its ability to execute many
clusters of instructions, or threads, in parallel, greatly accelerating many
academic tasks.
By definition and by design, an Arm processor is not a GPU, though a system
could be constructed using both. Last November, Nvidia announced its
introduction of a reference platform enabling systems architects to couple
Arm-based server designs with Nvidia GPU accelerators.
WHAT'S THE RELATIONSHIP BETWEEN ARM AND APPLE?
Apple CEO Tim Cook announces his company's chip manufacturing unit at WWDC
2020.
Apple Silicon is the phrase Apple presently uses to describe its own
processor production, beginning last June with Apple's announcement of the
replacement of its x86 Mac processor line. In its place, in Mac laptop units
that are reportedly already shipping, will be a new system-on-a-chip called
A12Z, code-named "Bionic," produced by Apple using the 64-bit instruction
set licensed to it by Arm Holdings. In this case, Arm isn't the designer,
but the producer of the instruction set around which Apple makes its
original design. Apple is widely expected to choose TSMC as the fabricator
for its A12Z.
For MacOS 11 to continue to run software compiled for Intel processors, the
new Apple system will run a kind of "just-in-time" instruction translator
called Rosetta 2. Rather than run an old MacOS image in a virtual machine,
the new OS will run a live x86 machine code translator that re-fashions x86
code into what Apple now calls Universal 2 binary code -- an
intermediate-level code that can still be made to run on older Intel-based
Macs -- in real-time. That code will run in what sources outside of Apple
call an "emulator," but which isn't really an emulator in that it doesn't
simulate the execution of code in an actual, physical machine (there is no
"Universal 2" chip).
The first results of independent performance benchmarks comparing an iPad
Pro using the A12Z chip planned for the first Arm-based Macs, against
Microsoft Surface models, looked promising. Geekbench results give the
Bionic-powered tablet a multi-core processing score of 4669 (higher is
better), versus 2966 for the Pentium-powered Surface Pro X, and 3033 for the
Core i5-powered Surface Pro 6.
Apple's newly claimed ability to produce its own SoC for Mac, just as it
does for iPhone and iPad, could save the company over time as much as 60
percent on production costs, according to its own estimates. Of course,
Apple is typically tight-lipped as to how it arrives at that estimate, and
how long such savings will take to be realized.
The relationship between Apple and Arm Holdings dates back to 1990, when
Apple Computer UK became a founding co-stakeholder. The other co-partners at
that time were the Arm concept's originator, Acorn Computers Ltd. (more
about Acorn later) and custom semiconductor maker VLSI Technology (named for
the common semiconductor manufacturing process called "very large-scale
integration"). Today, Arm Holdings is a wholly-owned subsidiary of SoftBank,
which announced its intent to purchase the licensor in July 2016. At the
time, the acquisition deal was the largest for a Europe-based technology
firm.
WHY X86 IS SOLD AND ARM IS LICENSED
The maker of an Intel- or AMD-based x86 computer does not design nor does it
own any portion of the intellectual property for the CPU. It also cannot
reproduce x86 IP for its own purposes. "Intel Inside" is a seal certifying a
license for the device manufacturer to build a machine around Intel's
processor. An Arm-based device may be designed to incorporate the processor,
perhaps even making adaptations to its architecture and functionality. For
that reason, rather than a "central processing unit" (CPU), an Arm processor
is instead called a system-on-a-chip (SoC). Much of the functionality of the
device may be fabricated onto the chip itself, cohabiting the die with Arm's
exclusive cores, rather than built around the chip in separate processors,
accelerators, or expansions.
As a result, a device run by an Arm processor, such as one of the Cortex
series, is a different order of machine from one run by an Intel Xeon or an
AMD Epyc. It means something quite different to be an original device based
around an Arm chip. Most importantly from a manufacturer's perspective, it
means a somewhat different, and hopefully more manageable, supply chain.
Since Arm has no interest in marketing itself to end-users, you don't
typically hear much about "Arm Inside."
Equally important, however, is the fact that an Arm chip is not necessarily
a central processor. Depending on the design of its system, it can be the
heart of a device controller, a microcontroller (MCU), or some other
subordinate component in a system.
Perhaps the best explanation of Arm's business model, as well as its
relationship with its own intellectual property, is to be found in a 2002
filing with the US Securities and Exchange Commission:
We take great care to establish and maintain the proprietary integrity of
our products. We focus on designing and implementing our products in a
"cleanroom" fashion, without the use of intellectual property belonging to
other third parties, except under strictly maintained procedures and express
license rights. In the event that we discover that a third party has
intellectual property protections covering a product that we are interested
in developing, we would take steps to either purchase a license to use the
technology or work around the technology in developing our own solution so
as to avoid infringement of that other company's intellectual property
rights. Notwithstanding such efforts, third parties may yet make claims that
we have infringed their proprietary rights, which we would defend.
What types of Arm processors are produced today?
To stay competitive, Arm offers a variety of processor core styles or
series. Some are marketed for a variety of use cases; others are earmarked
for just one or two. It's important to note here that Intel uses the term
"microarchitecture," and sometimes by extension "architecture," to refer to
the specific stage of evolution of its processors' features and
functionality -- for example, its most recently shipped generation of Xeon
server processors is a microarchitecture Intel has codenamed Cascade Lake.
By comparison, Arm architecture encompasses the entire history of Arm RISC
processors. Each iteration of this architecture has been called a variety of
things, but most recently a series. All that having been said, Arm
processors' instruction sets have evolved at their own pace, with each
iteration generally referred to using the same abbreviation Intel uses for
x86: ISA. And yes, here the "A" stands for "architecture."
Intel manufactures Celeron, Core, and Xeon processors for very different
classes of customers; AMD manufactures Ryzen for desktop and laptop
computers, and Epyc for servers. By contrast, Arm produces designs for
complete processors, that may be utilized by partners as-is, or customized
by those partners for their own purposes. Here are the principal Arm
Holdings, Ltd. designs at the time of this publication:
- Cortex-A has been marketed as the workhorse of the Arm family, with the "A" in this instance standing for application. As originally conceived, the client looking to build a system around Cortex-A had a particular application in mind for it, such as a digital audio amplifier, digital video processor, the microcontroller for a fire suppression system, or a sophisticated heart rate monitor. As things turned out, Cortex-A ended up being the heart of two emerging classes of device: Single-board computers capable of being programmed for a variety of applications, such as cash register processing; and most importantly of all, smartphones. Importantly, Cortex-A processors include memory management units (MMU) on-chip. Decades ago, it was the inclusion of the MMU on-chip by Intel's 80286 CPU that changed the game in its competition against Motorola chips, which at that time-powered Macintosh. The principal tool in Cortex-A's arsenal is its advanced single-instruction, multiple-data (SIMD) instruction set, code-named NEON, which executes instructions like accessing memory and processing data in parallel over a larger set of vectors. Imagine pulling into a filling station and loading up with enough fuel for 8 or 16 tanks, and you'll get the basic idea.
- Cortex-R is a class of processor with a much narrower set of use cases: Mainly microcontroller applications that require real-time processing. One big case-in-point is 4G LTE and 5G modems, where time (or what a music composer might more accurately call "tempo") is a critical factor in achieving modulation. Cortex-R's architecture is tailored in such a way that it responds to interrupts -- the requests for attention that trigger processes to run -- not only quickly but predictably. This enables R to run more consistently and deterministically and is one reason why Arm is promoting its use as a high-capacity storage controller for solid-state flash memory.
- Cortex-M is a more miniaturized form factor, making it more suitable for tight spaces: For example, automotive control and braking systems, and high-definition digital cameras with image recognition. A principal use for M is as a digital signal processor (DSP), which responds to and manages analog signals for applications such as sound synthesis, voice recognition, and radar. Since 2018, Arm has taken to referring to all its Cortex series collectively under the umbrella term Cosmos.
- Ethos-N is a series of processor specifically intended for applications that may involve machine learning or some other form of neural network processing. Arm calls this series a neural processor, although it's not quite the same class as Google's tensor processing unit, which Google itself admits is actually a co-processor and not a stand-alone controller [PDF]. Arm's concept of the neural processor includes routines used in drawing logical inferences from data, which are the building blocks of artificial intelligence used in image and pattern recognition, as well as machine learning.
- Ethos-U is a slimmed-down edition of Ethos-N that is designed to work more like a co-processor, particularly in conjunction with Cortex-A.
- Neoverse, launched in October 2018, represents a new and more concentrated effort by Arm to design cores that are more applicable in servers and the data centers that host them -- especially the smaller varieties. The term Arm uses in marketing Neoverse is "infrastructure" -- without being too specific, but still targeting the emerging use cases for mini and micro data centers stationed at the "customer edge," closer to where end-users will actually consume processor power.
- SecurCore is a class of processor designed by Arm exclusively for use in smart card, USB-based certification, and embedded security applications.
- These are series whose designs are licensed for others to produce processors and microcontrollers. All this being said, Arm also licenses certain custom and semi-custom versions of its architecture exclusively, enabling these clients to build unique processors that are available to no other producer. These special clients include:
Apple, which has fabricated for itself a variety of Arm-based designs over
the years for iPhone and iPad, and announced last June an entirely new SoC
for Mac (see above);
Marvell, which acquired chip maker Cavium in November 2017, and has since
doubled down on investments in the ThunderX series of processors originally
designed for Cavium;
- Nvidia, which co-designed two processor series with Arm, the most recent of which is called CArmel. Known generally as a GPU producer, Nvidia leverages the CArmel design to produce its 64-bit Tegra Xavier SoC. That chip powers the company's small-form-factor edge computing device, called Jetson AGX Xavier.
- Samsung, which produces a variety of 32-bit and 64-bit Arm processors for its entire consumer electronics line, under the internal brand Exynos. Some have used a Samsung core design called Mongoose, while most others have utilized versions of Cortex-A. Notably (or perhaps notoriously) Samsung manufactures variations of its Galaxy Note, Galaxy S, and Galaxy A series smartphones with either its own Exynos SoCs (outside the US) or Qualcomm Snapdragons (the US only).
- Qualcomm, whose most recent Snapdragon SoC models utilize a core design called Kryo, which is a semi-custom variation of Cortex-A. Earlier Snapdragon models were based on a core design called Krait, which was still officially an Arm-based SoC even though it was a purely Qualcomm design. Analysts estimate Snapdragon 855, 855 Plus, and 865 together to comprise the nucleus of greater than half the world's 5G smartphones. Although Qualcomm did give it a go in November 2017 with producing Arm chips for data center servers, with a product line called Centriq, it began winding down production of that line in December 2018, turning over the rights to continue its production to China-based Huaxintong Semiconductor (HXT), at the time a joint venture partner. That partnership was terminated the following April.
Ampere Computing, a startup launched with ex-Intel president Renee James,
produces a super-high core-count server processor line called Altra. The
128-core Altra Max edition will begin sampling in Q4 2020, notwithstanding
the pandemic.
IS A SYSTEM-ON-A-CHIP THE SAME AS A CHIPSET?
Technically speaking, the class of processor to which an Arm chip belongs is
an application-specific integrated circuit (ASIC). Consider a hardware
platform whose common element is a set of processing cores. That's not too
difficult; that describes essentially every device ever manufactured. But
miniaturize these components so that they all fit on one die -- on the same
physical platform -- interconnected using an exclusive mesh bus.
As you know, for a computer, the application program is rendered as
software. In many appliances such as Internet routers, front-door security
systems, and "smart" HDTVs, the memory in which operations programs are
stored is non-volatile, so we often call it firmware. In a device whose core
processor is an ASIC, its main functionality is rendered onto the chip, as a
permanent component. So the functionality that makes a device a "system"
shares the die with the processor cores, and an Arm chip can have dozens of
those.
Some analysis firms have taken to using the broad phrase applications
processor, or AP, to refer to ASICs, but this has not caught on generally.
In more casual use, an SoC is also called a chipset, even though in recent
years, more often than not, the number of chips in the set is just one. In
general use, a chipset is a set of one or more processors that collectively
function as a complete system. A CPU executes the main program, while a
chipset manages attached components and communicates with the user. On a PC
motherboard, the chipset is separate from the CPU. On an SoC, the main
processor and the system components share the same die.
What makes Arm processor architecture unique?
The "R" in "Arm" actually stands for another acronym: Reduced Instruction
Set Computer (RISC). Its purpose is to leverage the efficiency of
simplicity, to render all of the processor's functionality on a single chip.
Keeping a processor's instruction set small means it can be coded using a
fewer number of bits, thus reducing memory consumption as well as execution
cycle time. Back in 1982, students at the University of California,
Berkeley, were able to produce the first working RISC architectures by
judiciously selecting which functions would be used most often, and
rendering only those in hardware -- with the remaining functions rendered as
software. Indeed, that's what makes an SoC with a set of small cores
feasible: Relegating as much functionality to software as possible.
Retroactively, architectures such as x86, which adopted strategies quite
opposite to RISC, were dubbed Complex Instruction Set Computers (CISC),
although Intel has historically avoided using that term for itself. The
power of x86 comes from being able to accomplish so much with just a single
instruction. For instance, with Intel's vector processing, it's possible to
execute 16 single-precision math operations, or 8 double-precision
operations, simultaneously; here, the vector acts as a kind of "skewer," if
you will, poking through all the operands in a parallel operation and
racking them up.
That makes complex math easier, at least conceptually. With a RISC system,
math operations are decomposed into fundamentals. Everything that would
happen automatically with a CISC architecture -- for example, clearing up
the active registers when a process is completed -- takes a full, recorded
step with RISC. However, because fewer bits (binary digits) are required to
encapsulate the entire RISC instruction set, it may end up taking about as
many bits in the end to encode a sequence of fundamental operations in a
RISC processor -- perhaps even fewer -- than a complex CISC instruction
where all the properties and arguments are piled together in a big clump.
Intel can, and has, demonstrated very complex instructions with higher
performance statistics than the same processes for Arm processors, or other
RISC chips. But sometimes such performance gains come at an overall
performance cost for the rest of the system, making RISC architectures
somewhat more efficient than CISC at general-purpose tasks.
Then there's the issue of customization. Intel enhances its more premium
CPUs with functionality by way of programs that would normally be rendered
as software, but are instead embedded as microcode. These are routines
designed to be quickly executed at the machine code level, and that can be
referenced by that code indirectly, by name. This way, for example, a
program that needs to invoke a common method for decrypting messages on a
network can address very fast processor code, very close to where that code
will be executed. (Conveniently, many of the routines that end up in
microcode are the ones often employed in performance benchmarks.) These
microcode routines are stored in read-only memory (ROM) near the x86 cores.
An Arm processor, by contrast, does not use digital microcode in its on-die
memory. The current implementation of Arm's alternative is a concept called
custom instructions [PDF]. It enables the inclusion of completely
client-customizable, on-die modules, whose logic is effectively
"pre-decoded." These modules are represented in the above Arm diagram by the
green boxes. All the program has to do to invoke this logic is cue up a
dependent instruction for the processor core, which passes control to the
custom module as though it were another arithmetic logic unit (ALU). Arm
asks its partners who want to implement custom modules to present it with a
configuration file, and map out the custom data path from the core to the
custom ALU. Using just these items, the core can determine the dependencies
and instruction interlocking mechanisms for itself.
This is how an Arm partner builds up an exclusive design for itself, using
Arm cores as their starting ingredients.
Although Arm did not create the concept of RISC, it had a great deal to do
with realizing the concept, and making it publicly available. One branch of
the original Berkeley architecture to have emerged unto its own is RISC-V,
whose core specification was made open source under the Creative Commons 4.0
license. Nvidia, among others including Qualcomm, Samsung, Huawei, and
Micron Technology, has been a founding member of the RISC-V Foundation. When
asked, Nvidia CEO Jensen Huang indicated he intends for his company to
continue contributing to the RISC-V effort, maintaining that its ecosystem
is naturally separate from that of Arm.
The rising prospects for Arm in servers
RIKEN Center for Computational Science
Just last month, a Fujitsu Arm-powered supercomputer named Fugaku (pictured
left), built for Japan's RIKEN Center for Computational Science, seized the
#1 spot on the semi-annual Top 500 Supercomputer list.
But of all the differences between an x86 CPU and an Arm SoC, this may be
the only one that matters to a data center's facilities manager: Given any
pair of samples of both classes of processor, it's the Arm chip that is
least likely to require an active cooling system. Put another way, if you
open up your smartphone, chances are you won't find a fan. Or a liquid
cooling apparatus.
The buildout of 5G wireless technology is, ironically enough, expanding the
buildout of fiber optic connectivity to locations near the "customer edge"
-- the furthest point from the network operations center. This opens up the
opportunity to station edge computing devices and servers at or near such
points, but preferably without the heat exchanger units that typically
accompany racks of x86 servers.
Bamboo Systems
This is where startups such as Bamboo Systems come in. Radical reductions in
the size and power requirements for cooling systems enable server designers
to devise new ways to think "out-of-the-box" -- for instance, by shrinking
the box. A Bamboo server node is a card not much larger than the span of
most folks' hands, eight of which may be securely installed in a 1U box that
typically supports 1, maybe 2, x86 servers. Bamboo aims to produce servers,
the company says, that use as little as one-fifth the rack space and consume
one-fourth the power, of x86 racks with comparable performance levels.
Where did Arm processors come from?
An Acorn. Indeed, that's what the "A" originally stood for.
Back in 1981, a Cambridge, UK-based company called Acorn Computers was
marketing a microcomputer (what we used to call "PCs" back before IBM
popularized the term) based on Motorola's 6502 processor -- which had
powered the venerable Apple II, the Commodore 64, and the Atari 400 and 800.
Although the name "Acorn" was a clever trick to appear earlier on an
alphabetized list than "Apple," its computer had been partly subsidized by
the BBC and was thus known nationwide as the BBC Micro.
All 6502-based machines used 8-bit processor architecture, and in 1981,
Intel was working towards a fully compatible 16-bit architecture to replace
the 8086 used in the IBM PC/XT. The following year, Intel's 80286 would
enable IBM to produce its PC AT so that MS-DOS, and all the software that
ran on DOS, would not have to be changed or recompiled to run on 16-bit
architecture. It was a tremendous success, and Motorola could not match it.
Although Apple's first Macintosh was based on the 16-bit Motorola 68000
series, its architecture was only "inspired" by the earlier 8-bit design,
not compatible with it. (Eventually, it would produce a 16-bit Apple IIGS
based on the 65C816 processor, but only after several months waiting for the
makers of the 65816 to ship a working test model. The IIGS did have an
"Apple II" step-down mode but technically not full compatibility.)
Acorn's engineers wanted a way forward, and Motorola was leaving them at a
dead end. After experimenting with a surprisingly fast co-processor for the
6502 called Tube that just wasn't fast enough, they opted to take the plunge
with a full 32-bit pipeline. Following the lead of the Berkeley RISC
project, in 1983, they built a simulator for a processor they called Arm1
that was so simple, it ran on the BASIC language interpreter of the BBC
Micro (albeit not at speed). They would collaborate with VLSI and would
produce two years later their first Arm1 working model, with a 6 MHz clock
speed. It utilized so little power that, as one project engineer tells the
story, one day they noticed the chip was running without its power supply
connected. It was actually being powered by leakage from the power rails
leading to the I/O chip.
At this early stage, the Arm1, Arm2, and Arm3 processors were all
technically CPUs, not SoCs. Yet in the same sense that today's Intel Core
processors are architectural successors of its original 4004, Cortex-A is
the architectural successor to Arm1.
More Information:
Supercomputer Fugaku Documents
https://www.zdnet.com/article/introducing-the-arm-processor-again-what-you-should-know-about-it-now/
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