The Cell Broadband Engine

In 2000, while enjoying the successful release of the PlayStation 2 computer entertainment system, Ken Kutaragi, president and CEO of Sony Computer Entertainment Inc. (SCEI) was already thinking about ways to improve upon the design. After reviewing every microprocessor available from IBM, Kutaragi challenged the company to develop something new for the future PLAYSTATION 3—a revolutionary microprocessor that would deliver performance and efficiency beyond what was achievable even with conventional multi-core architectures. Toshiba Corporation joined in the challenge, and the three companies established the STI (Sony Group-Toshiba-IBM) Design Center in Austin, Texas, in the spring of 2001. More than 400 engineers would come together from the three companies spread out over 11 sites to design a “supercomputer on a chip.”

Cell Broadband Engine Architecture

The Cell Broadband Engine Architecture integrates an IBM PowerPC processor element (PPE) and eight synergistic processor elements (SPEs) in a unified system architecture. The PPE provides common system functions, while the SPEs perform data-intensive processing. The element interconnect bus (EIB) connects the processor elements with a high-performance communication subsystem.

IBM Roadrunner supercomputer

The IBM Roadrunner supercomputer was built for the US Department of Energy’s (DOE) National Nuclear Security Administration. With a total of 12,960 PowerXCell 8i processors, this supercomputer became the world’s fastest computer on June 18, 2008, with a sustained performance of 1.026 petaflops (1.02 quadrillion calculations per second).

Although the original challenge was to develop a processor for use in a specific gaming console, the engineers at the STI Design Center focused on developing something that would support multiple applications and systems. As a 2005 Forbes magazine article explained, “If its builders’ advance hype is right, Cell promises a new era of graphics-rich computers, as well as TV sets and home theaters capable of processing and moving large volumes of high-definition content.”

After four years of collaboration between the companies, both within the STI Design Center in Austin, and at several IBM Research centers around the world, the Cell Broadband Engine Architecture (CBEA) was born. Its first prototype was produced at IBM’s semiconductor manufacturing plant in East Fishkill, NY. The Linux ^® operating system was installed on the Cell Broadband Engine™ (Cell/B.E.) processor and tested. Over the next year, engineers worked on integrating the device into the PLAYSTATION 3 console so it could be demonstrated at the 2005 Electronics Entertainment Expo in Los Angeles, California.

The Cell/B.E. processor features a configuration of nine independent cores: one IBM ^® PowerPC ^® processing element (PPE) and eight synergistic processing elements (SPEs). The PPE is a new core unlike any other PowerPC core made by IBM in the past. It serves as a general-purpose microprocessor, running the operating system. The eight SPEs, which comprise the majority of the Cell/B.E. die, are designed specifically to perform high-speed calculations. Unlike conventional processors that rely on the hardware to automatically bring data and instructions close to the processor with a hierarchy of hardware caches, the Cell Broadband Engine requires the programmer to create a “shopping list” of the data that the program requires. In today’s processors, hardware caches occupy the majority of the area in a processor, so while the Cell Broadband Engine places a larger burden on the programmer—who must specify the needed data in advance of execution—the reduction of area needed for hardware caches allows the Cell Broadband Engine to realize eight SPEs and one conventional core in a technology that supports only two conventional high-performance cores.

“The processor platform that people have only been able to imagine is now going to become a reality. … The new broadband processor, code-named Cell, that we are going to create, will raise the curtain on a new era in high-speed, network-based computing. With built-in broadband connectivity, microprocessors that currently exist as individual islands will be more closely linked, making a network of systems act more as one, unified ‘supersystem.’ Just as biological cells in the body unite to form complete physical systems, Cell-based electronic products of all types will form the building blocks of larger systems. SCEI, IBM and Toshiba are mapping out the future of broadband computing.”

Ken Kutaragi

PRESIDENT AND CEO, SONY COMPUTER ENTERTAINMENT INC.

“Sony, IBM, and Toshiba Join Forces to create the ‘Cell’,” Neoseeker.com

March 12, 2001

“Later this year millions of homes will get a new supercomputer for the living room. Or maybe the playroom. Sony’s long-awaited PlayStation 3 game console, a slender yet muscular machine the size of a DVD player, performs a mind-boggling 2 trillion calculations per second. This kind of power, once reserved for seismic exploration and nuclear-weapons design, will let programmers create videogames that look as realistic as film.”

“Holy Chip!” Forbes

January 30, 2006

“In 2005, the Lawrence Berkeley National Laboratory studied the Cell’s computational performance and recorded their findings in the report The Potential of the Cell Processor for Scientific Computing. ... The study justifies the outrageous marketing claims: The Cell really provides supercomputer-like capability for nearly the cost and power (approximately 50 to 60 W) of a regular CPU.”

Matthew Scarpino in Programming the Cell Processor: For Games, Graphics, and Computation

October 14, 2008

“The PC is no longer the driving force in semiconductor innovation,” said John Kelly, senior vice president and group executive for the IBM Technology Group. “Networking and consumer electronics applications are driving the evolution of a new semiconductor industry—one based on closer collaboration with customers.”

In 2007, IBM challenged university students to develop Cell-based applications in the Cell Broadband Engine Processor University Challenge. Almost 80,000 students in 25 countries participated in the challenge. The first-place winners—students Jayram Moorkanikara Nageswaran and Jeff Furlong from the University of California, Irvine, and Ashok Chandrashekar and Andrew Felch from the Neukom Institute for Computational Science at Dartmouth College in New Hampshire—used a cluster of PLAYSTATION 3 consoles to perform large-scale modeling of the human brain.

A year later, in 2008, IBM announced a revised variant of the Cell called the IBM ^® PowerXCell 8i, which is available in IBM BladeCenter ^® QS22 servers. IBM also built the first Cell-based supercomputer, IBM Roadrunner, which consists of 12,960 PowerXCell 8i processors, along with 6562 AMD Opteron processors. In 2008, the Roadrunner supercomputer was the first to break the petaflop barrier, reaching a processing speed of 1.026 petaflops [read more about the Icon of Progress, Breaking the Petaflop Barrier]. In 2010, Toshiba announced a new line of TVs based on the Cell processor.

Selected team members who contributed to this Icon of Progress:

Jim Kahle IBM Fellow and former director of technology for the STI Design Center; had overall technical responsibility for the development of the Cell Broadband Engine
Peter Hofstee Senior technical staff member in the STI Design Center in Austin, Texas, chief scientist for the Cell Broadband Engine and chief architect of the synergistic processor element
Ken Kutaragi Hononary Chairman of Sony Computer Entertainment Inc.; brought together Sony, Toshiba and IBM to form the STI alliance that developed Cell Broadband Engine Architecture
John Kelly Senior vice president and group executive for IBM’s Technology Group; worked with executives from Sony and Toshiba to develop the STI Design Center where the Cell Broadband Engine was designed
Bijan Davari IBM Fellow and vice president, next-generation computing systems and technology; had responsibility for Cell-based systems (Quasar program)