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89-518: Cell , a shorthand for Cell Broadband Engine Architecture , is a 64-bit multi-core microprocessor and microarchitecture that combines a general-purpose PowerPC core of modest performance with streamlined coprocessing elements which greatly accelerate multimedia and vector processing applications, as well as many other forms of dedicated computation. It was developed by Sony , Toshiba , and IBM , an alliance known as "STI". The architectural design and first implementation were carried out at

178-532: A PCI Express accelerator board based on the PowerXCell 8i processor. Sony's high-performance media computing server ZEGO uses a 3.2 GHz Cell/B.E processor. The Cell Broadband Engine , or Cell as it is more commonly known, is a microprocessor intended as a hybrid of conventional desktop processors (such as the Athlon 64 , and Core 2 families) and more specialized high-performance processors, such as

267-404: A big.LITTLE core includes a high-performance core (called 'big') and a low-power core (called 'LITTLE'). There is also a trend towards improving energy-efficiency by focusing on performance-per-watt with advanced fine-grain or ultra fine-grain power management and dynamic voltage and frequency scaling (i.e. laptop computers and portable media players ). Chips designed from the outset for

356-502: A 90 nm process. An SPE can operate on sixteen 8-bit integers, eight 16-bit integers, four 32-bit integers, or four single-precision floating-point numbers in a single clock cycle, as well as a memory operation. Note that the SPU cannot directly access system memory; the 64-bit virtual memory addresses formed by the SPU must be passed from the SPU to the SPE memory flow controller (MFC) to set up

445-460: A DMA operation within the system address space. In one typical usage scenario, the system will load the SPEs with small programs (similar to threads ), chaining the SPEs together to handle each step in a complex operation. For instance, a set-top box might load programs for reading a DVD, video and audio decoding, and display and the data would be passed off from SPE to SPE until finally ending up on

534-456: A SIMD engine and Picochip with 300 processors on a single die, focused on communication applications. In heterogeneous computing , where a system uses more than one kind of processor or cores, multi-core solutions are becoming more common: Xilinx Zynq UltraScale+ MPSoC has a quad-core ARM Cortex-A53 and dual-core ARM Cortex-R5. Software solutions such as OpenAMP are being used to help with inter-processor communication. Mobile devices may use

623-451: A big factor in mobile devices that operate on batteries. Since each core in a multi-core CPU is generally more energy-efficient, the chip becomes more efficient than having a single large monolithic core. This allows higher performance with less energy. A challenge in this, however, is the additional overhead of writing parallel code. Maximizing the usage of the computing resources provided by multi-core processors requires adjustments both to

712-413: A combination of cores. Embedded computing operates in an area of processor technology distinct from that of "mainstream" PCs. The same technological drives towards multi-core apply here too. Indeed, in many cases the application is a "natural" fit for multi-core technologies, if the task can easily be partitioned between the different processors. In addition, embedded software is typically developed for

801-452: A crossbar switch, and the way the bus is designed, you could actually pull out the EIB and put in a crossbar switch if you were willing to devote more silicon space on the chip to wiring. We had to find a balance between connectivity and area, and there just was not enough room to put a full crossbar switch in. So we came up with this ring structure which we think is very interesting. It fits within

890-448: A given time period, since individual signals can be shorter and do not need to be repeated as often. Assuming that the die can physically fit into the package, multi-core CPU designs require much less printed circuit board (PCB) space than do multi-chip SMP designs. Also, a dual-core processor uses slightly less power than two coupled single-core processors, principally because of the decreased power required to drive signals external to

979-513: A large number of cores (rather than having evolved from single core designs) are sometimes referred to as manycore designs, emphasising qualitative differences. The composition and balance of the cores in multi-core architecture show great variety. Some architectures use one core design repeated consistently ("homogeneous"), while others use a mixture of different cores, each optimized for a different, " heterogeneous " role. How multiple cores are implemented and integrated significantly affects both

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1068-418: A list of 2 to 2048 such blocks. One of the major design decisions in the architecture of Cell is the use of DMAs as a central means of intra-chip data transfer, with a view to enabling maximal asynchrony and concurrency in data processing inside a chip. The PPE, which is capable of running a conventional operating system, has control over the SPEs and can start, stop, interrupt, and schedule processes running on

1157-605: A local memory of 256 KB. In total, the SPEs have 2 MB of local memory. The EIB is a communication bus internal to the Cell processor which connects the various on-chip system elements: the PPE processor, the memory controller (MIC), the eight SPE coprocessors, and two off-chip I/O interfaces, for a total of 12 participants in the PS3 (the number of SPU can vary in industrial applications). The EIB also includes an arbitration unit which functions as

1246-476: A new abstraction for C++ parallelism called TBB . Other research efforts include the Codeplay Sieve System , Cray's Chapel , Sun's Fortress , and IBM's X10 . Multi-core processing has also affected the ability of modern computational software development. Developers programming in newer languages might find that their modern languages do not support multi-core functionality. This then requires

1335-452: A new op every three cycles. Each transfer always takes eight beats. That was one of the simplifications we made, it's optimized for streaming a lot of data. If you do small ops, it does not work quite as well. If you think of eight-car trains running around this track, as long as the trains aren't running into each other, they can coexist on the track. Each participant on the EIB has one 16-byte read port and one 16-byte write port. The limit for

1424-446: A peak combined input speed of 25.6 GB/s and a peak combined output speed of 35 GB/s. To add further to the confusion, some older publications cite EIB bandwidth assuming a 4 GHz system clock. This reference frame results in an instantaneous EIB bandwidth figure of 384 GB/s and an arbitration-limited bandwidth figure of 256 GB/s. Multi-core processor A multi-core processor implements multiprocessing in

1513-405: A perceived lack of motivation for writing consumer-level threaded applications because of the relative rarity of consumer-level demand for maximum use of computer hardware. Also, serial tasks like decoding the entropy encoding algorithms used in video codecs are impossible to parallelize because each result generated is used to help create the next result of the entropy decoding algorithm. Given

1602-498: A set of traffic lights. In some documents, IBM refers to EIB participants as 'units'. The EIB is presently implemented as a circular ring consisting of four 16-byte-wide unidirectional channels which counter-rotate in pairs. When traffic patterns permit, each channel can convey up to three transactions concurrently. As the EIB runs at half the system clock rate the effective channel rate is 16 bytes every two system clocks. At maximum concurrency , with three active transactions on each of

1691-793: A single FPGA . Each "core" can be considered a " semiconductor intellectual property core " as well as a CPU core. While manufacturing technology improves, reducing the size of individual gates, physical limits of semiconductor -based microelectronics have become a major design concern. These physical limitations can cause significant heat dissipation and data synchronization problems. Various other methods are used to improve CPU performance. Some instruction-level parallelism (ILP) methods such as superscalar pipelining are suitable for many applications, but are inefficient for others that contain difficult-to-predict code. Many applications are better suited to thread-level parallelism (TLP) methods, and multiple independent CPUs are commonly used to increase

1780-453: A single die with a unified cache, hence any two working dual-core dies can be used, as opposed to producing four cores on a single die and requiring all four to work to produce a quad-core CPU. From an architectural point of view, ultimately, single CPU designs may make better use of the silicon surface area than multiprocessing cores, so a development commitment to this architecture may carry the risk of obsolescence. Finally, raw processing power

1869-426: A single participant is to read and write at a rate of 16 bytes per EIB clock (for simplicity often regarded 8 bytes per system clock). Each SPU processor contains a dedicated DMA management queue capable of scheduling long sequences of transactions to various endpoints without interfering with the SPU's ongoing computations; these DMA queues can be managed locally or remotely as well, providing additional flexibility in

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1958-543: A single physical package. Designers may couple cores in a multi-core device tightly or loosely. For example, cores may or may not share caches , and they may implement message passing or shared-memory inter-core communication methods. Common network topologies used to interconnect cores include bus , ring , two-dimensional mesh , and crossbar . Homogeneous multi-core systems include only identical cores; heterogeneous multi-core systems have cores that are not identical (e.g. big.LITTLE have heterogeneous cores that share

2047-565: A specific hardware release, making issues of software portability , legacy code or supporting independent developers less critical than is the case for PC or enterprise computing. As a result, it is easier for developers to adopt new technologies and as a result there is a greater variety of multi-core processing architectures and suppliers. As of 2010 , multi-core network processors have become mainstream, with companies such as Freescale Semiconductor , Cavium Networks , Wintegra and Broadcom all manufacturing products with eight processors. For

2136-413: A system's overall TLP. A combination of increased available space (due to refined manufacturing processes) and the demand for increased TLP led to the development of multi-core CPUs. Several business motives drive the development of multi-core architectures. For decades, it was possible to improve performance of a CPU by shrinking the area of the integrated circuit (IC), which reduced the cost per device on

2225-419: A variety of integer and floating-point formats. System memory addresses for both the PPE and SPE are expressed as 64-bit values for a theoretic address range of 2 bytes (16 exabytes or 16,777,216 terabytes). In practice, not all of these bits are implemented in hardware. Local store addresses internal to the SPU (Synergistic Processor Unit) processor are expressed as a 32-bit word. In documentation relating to Cell

2314-399: A variety of specialty cores to run modular software scheduled by a high-level applications programming interface. [...] Atsushi Hasegawa, a senior chief engineer at Renesas , generally agreed. He suggested the cellphone's use of many specialty cores working in concert is a good model for future multi-core designs. [...] Anant Agarwal , founder and chief executive of startup Tilera , took

2403-564: A word is always taken to mean 32 bits, a doubleword means 64 bits, and a quadword means 128 bits. In 2008, IBM announced a revised variant of the Cell called the PowerXCell 8i , which is available in QS22 Blade Servers from IBM. The PowerXCell is manufactured on a 65 nm process, and adds support for up to 32 GB of slotted DDR2 memory, as well as dramatically improving double-precision floating-point performance on

2492-781: Is a common source of confusion. The PPE core is dual threaded and manifests in software as two independent threads of execution while each active SPE manifests as a single thread. In the PlayStation 3 configuration as described by Sony, the Cell processor provides nine independent threads of execution. On June 28, 2005, IBM and Mercury Computer Systems announced a partnership agreement to build Cell-based computer systems for embedded applications such as medical imaging , industrial inspection , aerospace and defense , seismic processing , and telecommunications . Mercury has since then released blades , conventional rack servers and PCI Express accelerator boards with Cell processors. In

2581-529: Is a heavy burden on the compiler). Each SPE has 6 execution units divided among odd and even pipelines on each SPE : The SPU runs a specially developed instruction set (ISA) with 128-bit SIMD organization for single and double precision instructions. With the current generation of the Cell, each SPE contains a 256  KiB embedded SRAM for instruction and data, called "Local Storage" (not to be mistaken for "Local Memory" in Sony's documents that refer to

2670-510: Is a significant ongoing topic of research. Cointegration of multiprocessor applications provides flexibility in network architecture design. Adaptability within parallel models is an additional feature of systems utilizing these protocols. In the consumer market, dual-core processors (that is, microprocessors with two units) started becoming commonplace on personal computers in the late 2000s. Quad-core processors were also being adopted in that era for higher-end systems before becoming standard. In

2759-421: Is described by Amdahl's law . In the best case, so-called embarrassingly parallel problems may realize speedup factors near the number of cores, or even more if the problem is split up enough to fit within each core's cache(s), avoiding use of much slower main-system memory. Most applications, however, are not accelerated as much unless programmers invest effort in refactoring . The parallelization of software

Cell (processor) - Misplaced Pages Continue

2848-410: Is designed to compensate for this with compiler assistance, in which prepare-to-branch instructions are created. For double-precision floating-point operations, as sometimes used in personal computers and often used in scientific computing, Cell performance drops by an order of magnitude, but still reaches 20.8 GFLOPS (1.8 GFLOPS per SPE, 6.4 GFLOPS per PPE). The PowerXCell 8i variant, which

2937-630: Is not the only constraint on system performance. Two processing cores sharing the same system bus and memory bandwidth limits the real-world performance advantage. The trend in processor development has been towards an ever-increasing number of cores, as processors with hundreds or even thousands of cores become theoretically possible. In addition, multi-core chips mixed with simultaneous multithreading , memory-on-chip, and special-purpose "heterogeneous" (or asymmetric) cores promise further performance and efficiency gains, especially in processing multimedia, recognition and networking applications. For example,

3026-506: Is the PowerPC based, dual-issue in-order two-way simultaneous-multithreaded CPU core with a 23-stage pipeline acting as the controller for the eight SPEs, which handle most of the computational workload. PPE has limited out of order execution capabilities; it can perform loads out of order and has delayed execution pipelines. The PPE will work with conventional operating systems due to its similarity to other 64-bit PowerPC processors, while

3115-527: The NVIDIA and ATI graphics-processors ( GPUs ). The longer name indicates its intended use, namely as a component in current and future online distribution systems; as such it may be utilized in high-definition displays and recording equipment, as well as HDTV systems. Additionally the processor may be suited to digital imaging systems (medical, scientific, etc. ) and physical simulation ( e.g. , scientific and structural engineering modeling). As used in

3204-457: The Pentium 4 and the Athlon 64 . However, comparing only floating-point abilities of a system is a one-dimensional and application-specific metric. Unlike a Cell processor, such desktop CPUs are more suited to the general-purpose software usually run on personal computers. In addition to executing multiple instructions per clock, processors from Intel and AMD feature branch predictors . The Cell

3293-547: The PowerXCell 8i , at the 65 nm feature size. In May 2008, an Opteron - and PowerXCell 8i-based supercomputer, the IBM Roadrunner system, became the world's first system to achieve one petaFLOPS, and was the fastest computer in the world until third quarter 2009. The world's three most energy-efficient supercomputers, as represented by the Green500 list, are similarly based on the PowerXCell 8i. In August 2009

3382-492: The operating system (OS) support and to existing application software. Also, the ability of multi-core processors to increase application performance depends on the use of multiple threads within applications. Integration of a multi-core chip can lower the chip production yields. They are also more difficult to manage thermally than lower-density single-core designs. Intel has partially countered this first problem by creating its quad-core designs by combining two dual-core ones on

3471-732: The same integrated circuit die ; separate microprocessor dies in the same package are generally referred to by another name, such as multi-chip module . This article uses the terms "multi-core" and "dual-core" for CPUs manufactured on the same integrated circuit, unless otherwise noted. In contrast to multi-core systems, the term multi-CPU refers to multiple physically separate processing-units (which often contain special circuitry to facilitate communication between each other). The terms many-core and massively multi-core are sometimes used to describe multi-core architectures with an especially high number of cores (tens to thousands ). Some systems use many soft microprocessor cores placed on

3560-435: The 45 nm Cell processor was introduced in concert with Sony's PlayStation 3 Slim . By November 2009, IBM had discontinued the development of a Cell processor with 32 APUs but was still developing other Cell products. On May 17, 2005, Sony Computer Entertainment confirmed some specifications of the Cell processor that would be shipping in the then-forthcoming PlayStation 3 console. This Cell configuration has one PPE on

3649-571: The Broadband Engine was meant to have 1 teraFLOPS of raw computing power in theory. The design with 4 PPEs and 32 SPEs was never realized. Instead, Sony and IBM only manufactured a design with one PPE and 8 SPEs. This smaller design, the Cell Broadband Engine or Cell/BE was fabricated using a 90 nm SOI process. In March 2007, IBM announced that the 65 nm version of Cell/BE was in production at its plant (at

Cell (processor) - Misplaced Pages Continue

3738-590: The Broadband Engine was shown to be a chip package comprising four "Processing Elements", which was the patent's description for what is now known as the Power Processing Element (PPE). Each Processing Element would contain 8 "Synergistic Processing Elements" ( SPEs ) on the chip. This chip package was supposed to run at a clock speed of 4 GHz and with 32 SPEs providing 32  gigaFLOPS each SPE (FP32 Single precision), (Per SPU 4 Flops FPU + 4 Flops by integers Unit: 8 Flops per Cycle Per Spu),

3827-495: The Cell processor but during development, Microsoft approached IBM wanting a high-performance processor core for its Xbox 360 . IBM complied and made the tri-core Xenon processor , based on a slightly modified version of the PPE with added VMX128 extensions. Each SPE is a dual issue in order processor composed of a "Synergistic Processing Unit", SPU, and a "Memory Flow Controller", MFC ( DMA , MMU , and bus interface). SPEs do not have any branch prediction hardware (hence there

3916-568: The Cell. The Cell architecture includes a memory coherence architecture that emphasizes power efficiency, prioritizes bandwidth over low latency , and favors peak computational throughput over the simplicity of program code . For these reasons, Cell is widely regarded as a challenging environment for software development . IBM provided a Linux -based development platform to help developers program for Cell chips. In mid-2000, Sony Computer Entertainment , Toshiba Corporation , and IBM formed an alliance known as "STI" to design and manufacture

4005-506: The IC. Alternatively, for the same circuit area, more transistors could be used in the design, which increased functionality, especially for complex instruction set computing (CISC) architectures. Clock rates also increased by orders of magnitude in the decades of the late 20th century, from several megahertz in the 1980s to several gigahertz in the early 2000s. As the rate of clock speed improvements slowed, increased use of parallel computing in

4094-572: The PPE, input/output elements and the SPEs, called the Element Interconnect Bus or EIB. To achieve the high performance needed for mathematically intensive tasks, such as decoding/encoding MPEG streams, generating or transforming three-dimensional data, or undertaking Fourier analysis of data, the Cell processor marries the SPEs and the PPE via EIB to give access, via fully cache coherent DMA (direct memory access) , to both main memory and to other external data storage. To make

4183-608: The PlayStation 3 it has 250 million transistors. In a simple analysis, the Cell processor can be split into four components: external input and output structures, the main processor called the Power Processing Element (PPE) (a two-way simultaneous-multithreaded PowerPC 2.02 core), eight fully functional co-processors called the Synergistic Processing Elements , or SPEs, and a specialized high-bandwidth circular data bus connecting

4272-934: The SPEs are designed for vectorized floating point code execution. The PPE contains a 32 KiB level 1 instruction cache , a 32 KiB level 1 data cache, and a 512 KiB level 2 cache. The size of a cache line is 128 bytes in all caches. Additionally, IBM has included an AltiVec (VMX) unit which is fully pipelined for single precision floating point (Altivec 1 does not support double precision floating-point vectors.), 32-bit Fixed Point Unit (FXU) with 64-bit register file per thread, Load and Store Unit (LSU) , 64-bit Floating-Point Unit (FPU) , Branch Unit (BRU) and Branch Execution Unit(BXU). PPE consists of three main units: Instruction Unit (IU), Execution Unit (XU), and vector/scalar execution unit (VSU). IU contains L1 instruction cache, branch prediction hardware, instruction buffers, and dependency checking logic. XU contains integer execution units (FXU) and load-store unit (LSU). VSU contains all of

4361-491: The SPEs from a peak of about 12.8  GFLOPS to 102.4 GFLOPS total for eight SPEs, which, coincidentally, is the same peak performance as the NEC SX-9 vector processor released around the same time. The IBM Roadrunner supercomputer, the world's fastest during 2008–2009, consisted of 12,240 PowerXCell 8i processors, along with 6,562 AMD Opteron processors. The PowerXCell 8i powered super computers also dominated all of

4450-410: The SPEs or the PPE. Both the PPE and SPE are RISC architectures with a fixed-width 32-bit instruction format. The PPE contains a 64-bit general-purpose register set (GPR), a 64-bit floating-point register set (FPR), and a 128-bit Altivec register set. The SPE contains 128-bit registers only. These can be used for scalar data types ranging from 8-bits to 64-bits in size or for SIMD computations on

4539-411: The SPEs. To this end, the PPE has additional instructions relating to the control of the SPEs. Unlike SPEs, the PPE can read and write the main memory and the local memories of SPEs through the standard load/store instructions. Despite having Turing complete architectures, the SPEs are not fully autonomous and require the PPE to prime them before they can do any useful work. As most of the "horsepower" of

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4628-645: The STI Design Center in Austin, Texas over a four-year period beginning March 2001 on a budget reported by Sony as approaching US$ 400 million. The first major commercial application of Cell was in Sony's PlayStation 3 game console , released in 2006. In May 2008, the Cell-based IBM Roadrunner supercomputer became the first TOP500 LINPACK sustained 1.0 petaflops system. Mercury Computer Systems also developed designs based on

4717-568: The TV. Another possibility is to partition the input data set and have several SPEs performing the same kind of operation in parallel. At 3.2 GHz, each SPE gives a theoretical 25.6 GFLOPS of single-precision performance. Compared to its personal computer contemporaries, the relatively high overall floating-point performance of a Cell processor seemingly dwarfs the abilities of the SIMD unit in CPUs like

4806-454: The VRAM) which is visible to the PPE and can be addressed directly by software. Each SPE can support up to 4 GiB of local store memory. The local store does not operate like a conventional CPU cache since it is neither transparent to software nor does it contain hardware structures that predict which data to load. The SPEs contain a 128-bit, 128-entry register file and measures 14.5 mm on

4895-662: The alternatives. An especially strong contender for established markets is the further integration of peripheral functions into the chip. The proximity of multiple CPU cores on the same die allows the cache coherency circuitry to operate at a much higher clock rate than what is possible if the signals have to travel off-chip. Combining equivalent CPUs on a single die significantly improves the performance of cache snoop (alternative: Bus snooping ) operations. Put simply, this means that signals between different CPUs travel shorter distances, and therefore those signals degrade less. These higher-quality signals allow more data to be sent in

4984-438: The area constraints and still has very impressive bandwidth. At 3.2 GHz, each channel flows at a rate of 25.6 GB/s. Viewing the EIB in isolation from the system elements it connects, achieving twelve concurrent transactions at this flow rate works out to an abstract EIB bandwidth of 307.2 GB/s. Based on this view many IBM publications depict available EIB bandwidth as "greater than 300 GB/s". This number reflects

5073-429: The best of EIB, and to overlap computation and data transfer, each of the nine processing elements (PPE and SPEs) is equipped with a DMA engine . Since the SPE's load/store instructions can only access its own local scratchpad memory , each SPE entirely depends on DMAs to transfer data to and from the main memory and other SPEs' local memories. A DMA operation can transfer either a single block area of size up to 16KB, or

5162-482: The chip layout had to be reworked, which resulted in both larger chip die and packaging. While the Cell chip can have a number of different configurations, the basic configuration is a multi-core chip composed of one "Power Processor Element" ("PPE") (sometimes called "Processing Element", or "PE"), and multiple "Synergistic Processing Elements" ("SPE"). The PPE and SPEs are linked together by an internal high speed bus dubbed "Element Interconnect Bus" ("EIB"). The PPE

5251-535: The chip. Furthermore, the cores share some circuitry, like the L2 cache and the interface to the front-side bus (FSB). In terms of competing technologies for the available silicon die area, multi-core design can make use of proven CPU core library designs and produce a product with lower risk of design error than devising a new wider-core design. Also, adding more cache suffers from diminishing returns. Multi-core chips also allow higher performance at lower energy. This can be

5340-412: The circular configuration they adopted to spare resources rarely represents a limiting factor on the performance of the Cell chip as a whole. In the worst case, the programmer must take extra care to schedule communication patterns where the EIB is able to function at high concurrency levels. David Krolak explained: Well, in the beginning, early in the development process, several people were pushing for

5429-401: The control model. Data flows on an EIB channel stepwise around the ring. Since there are twelve participants, the total number of steps around the channel back to the point of origin is twelve. Six steps is the longest distance between any pair of participants. An EIB channel is not permitted to convey data requiring more than six steps; such data must take the shorter route around the circle in

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5518-635: The core, with eight physical SPEs in silicon. In the PlayStation 3, one SPE is locked-out during the test process, a practice which helps to improve manufacturing yields, and another one is reserved for the OS, leaving 6 free SPEs to be used by games' code. The target clock-frequency at introduction is 3.2  GHz . The introductory design is fabricated using a 90 nm SOI process, with initial volume production slated for IBM's facility in East Fishkill, New York . The relationship between cores and threads

5607-430: The count can go over 10 million (and in one case up to 20 million processing elements total in addition to host processors). The improvement in performance gained by the use of a multi-core processor depends very much on the software algorithms used and their implementation. In particular, possible gains are limited by the fraction of the software that can run in parallel simultaneously on multiple cores; this effect

5696-507: The developer's programming skills and the consumer's expectations of apps and interactivity versus the device. A device advertised as being octa-core will only have independent cores if advertised as True Octa-core , or similar styling, as opposed to being merely two sets of quad-cores each with fixed clock speeds. The article "CPU designers debate multi-core future" by Rick Merritt, EE Times 2008, includes these comments: Chuck Moore [...] suggested computers should be like cellphones, using

5785-447: The documentation set as yet made public by IBM. In practice, effective EIB bandwidth can also be limited by the ring participants involved. While each of the nine processing cores can sustain 25.6 GB/s read and write concurrently, the memory interface controller (MIC) is tied to a pair of XDR memory channels permitting a maximum flow of 25.6 GB/s for reads and writes combined and the two IO controllers are documented as supporting

5874-405: The execution resources for FPU and VMX. Each PPE can complete two double-precision operations per clock cycle using a scalar fused-multiply-add instruction, which translates to 6.4  GFLOPS at 3.2 GHz; or eight single-precision operations per clock cycle with a vector fused-multiply-add instruction, which translates to 25.6 GFLOPS at 3.2 GHz. The PPE was designed specifically for

5963-548: The fall of 2006, IBM released the QS20 blade module using double Cell BE processors for tremendous performance in certain applications, reaching a peak of 410 gigaFLOPS in Fp32 Single precision per module. The QS22 based on the PowerXCell 8i processor was used for the IBM Roadrunner supercomputer. Mercury and IBM uses the fully utilized Cell processor with eight active SPEs. On April 8, 2008, Fixstars Corporation released

6052-457: The form of multi-core processors has been pursued to improve overall processing performance. Multiple cores were used on the same CPU chip, which could then lead to better sales of CPU chips with two or more cores. For example, Intel has produced a 48-core processor for research in cloud computing; each core has an x86 architecture. Since computer manufacturers have long implemented symmetric multiprocessing (SMP) designs using discrete CPUs,

6141-488: The four rings, the peak instantaneous EIB bandwidth is 96 bytes per clock (12 concurrent transactions × 16 bytes wide / 2 system clocks per transfer). While this figure is often quoted in IBM literature, it is unrealistic to simply scale this number by processor clock speed. The arbitration unit imposes additional constraints . IBM Senior Engineer David Krolak , EIB lead designer, explains the concurrency model: A ring can start

6230-416: The increasing emphasis on multi-core chip design, stemming from the grave thermal and power consumption problems posed by any further significant increase in processor clock speeds, the extent to which software can be multithreaded to take advantage of these new chips is likely to be the single greatest constraint on computer performance in the future. If developers are unable to design software to fully exploit

6319-457: The issues regarding implementing multi-core processor architecture and supporting it with software are well known. Additionally: In order to continue delivering regular performance improvements for general-purpose processors, manufacturers such as Intel and AMD have turned to multi-core designs, sacrificing lower manufacturing-costs for higher performance in some applications and systems. Multi-core architectures are being developed, but so are

6408-443: The late 2010s, hexa-core (six cores) started entering the mainstream and since the early 2020s has overtaken quad-core in many spaces. The terms multi-core and dual-core most commonly refer to some sort of central processing unit (CPU), but are sometimes also applied to digital signal processors (DSP) and system on a chip (SoC). The terms are generally used only to refer to multi-core microprocessors that are manufactured on

6497-497: The operating system of the network device. In digital signal processing the same trend applies: Texas Instruments has the three-core TMS320C6488 and four-core TMS320C5441, Freescale the four-core MSC8144 and six-core MSC8156 (and both have stated they are working on eight-core successors). Newer entries include the Storm-1 family from Stream Processors, Inc with 40 and 80 general purpose ALUs per chip, all programmable in C as

6586-408: The opposing view. He said multi-core chips need to be homogeneous collections of general-purpose cores to keep the software model simple. An outdated version of an anti-virus application may create a new thread for a scan process, while its GUI thread waits for commands from the user (e.g. cancel the scan). In such cases, a multi-core architecture is of little benefit for the application itself due to

6675-412: The other direction. The number of steps involved in sending the packet has very little impact on transfer latency: the clock speed driving the steps is very fast relative to other considerations. However, longer communication distances are detrimental to the overall performance of the EIB as they reduce available concurrency. Despite IBM's original desire to implement the EIB as a more powerful cross-bar,

6764-418: The other hand, on the server side , multi-core processors are ideal because they allow many users to connect to a site simultaneously and have independent threads of execution. This allows for Web servers and application servers that have much better throughput . Vendors may license some software "per processor". This can give rise to ambiguity, because a "processor" may consist either of a single core or of

6853-449: The peak instantaneous EIB bandwidth scaled by processor frequency. However, other technical restrictions are involved in the arbitration mechanism for packets accepted onto the bus. The IBM Systems Performance group explained: Each unit on the EIB can simultaneously send and receive 16 bytes of data every bus cycle. The maximum data bandwidth of the entire EIB is limited by the maximum rate at which addresses are snooped across all units in

6942-488: The problem, for example using a coordination language and program building blocks (programming libraries or higher-order functions). Each block can have a different native implementation for each processor type. Users simply program using these abstractions and an intelligent compiler chooses the best implementation based on the context. Managing concurrency acquires a central role in developing parallel applications. The basic steps in designing parallel applications are: On

7031-628: The processor. The STI Design Center opened in March 2001. The Cell was designed over a period of four years, using enhanced versions of the design tools for the POWER4 processor. Over 400 engineers from the three companies worked together in Austin, with critical support from eleven of IBM's design centers. During this period, IBM filed many patents pertaining to the Cell architecture, manufacturing process, and software environment. An early patent version of

7120-735: The resources provided by multiple cores, then they will ultimately reach an insurmountable performance ceiling. The telecommunications market had been one of the first that needed a new design of parallel datapath packet processing because there was a very quick adoption of these multiple-core processors for the datapath and the control plane. These MPUs are going to replace the traditional Network Processors that were based on proprietary microcode or picocode . Parallel programming techniques can benefit from multiple cores directly. Some existing parallel programming models such as Cilk Plus , OpenMP , OpenHMPP , FastFlow , Skandium, MPI , and Erlang can be used on multi-core platforms. Intel introduced

7209-587: The same instruction set , while AMD Accelerated Processing Units have cores that do not share the same instruction set). Just as with single-processor systems, cores in multi-core systems may implement architectures such as VLIW , superscalar , vector , or multithreading . Multi-core processors are widely used across many application domains, including general-purpose , embedded , network , digital signal processing (DSP), and graphics (GPU). Core count goes up to even dozens, and for specialized chips over 10,000, and in supercomputers (i.e. clusters of chips)

7298-462: The single thread doing all the heavy lifting and the inability to balance the work evenly across multiple cores. Programming truly multithreaded code often requires complex co-ordination of threads and can easily introduce subtle and difficult-to-find bugs due to the interweaving of processing on data shared between threads (see thread-safety ). Consequently, such code is much more difficult to debug than single-threaded code when it breaks. There has been

7387-538: The system comes from the synergistic processing elements, the use of DMA as a method of data transfer and the limited local memory footprint of each SPE pose a major challenge to software developers who wish to make the most of this horsepower, demanding careful hand-tuning of programs to extract maximal performance from this CPU. The PPE and bus architecture includes various modes of operation giving different levels of memory protection , allowing areas of memory to be protected from access by specific processes running on

7476-404: The system developer, a key challenge is how to exploit all the cores in these devices to achieve maximum networking performance at the system level, despite the performance limitations inherent in a symmetric multiprocessing (SMP) operating system. Companies such as 6WIND provide portable packet processing software designed so that the networking data plane runs in a fast path environment outside

7565-469: The system, which is one per bus cycle. Since each snooped address request can potentially transfer up to 128 bytes, the theoretical peak data bandwidth on the EIB at 3.2 GHz is 128Bx1.6 GHz = 204.8 GB/s. This quote apparently represents the full extent of IBM's public disclosure of this mechanism and its impact. The EIB arbitration unit, the snooping mechanism, and interrupt generation on segment or page translation faults are not well described in

7654-466: The time, now GlobalFoundries') in East Fishkill, New York , with Bandai Namco Entertainment using the Cell/BE processor for their 357 arcade board as well as the subsequent 369. In February 2008, IBM announced that it would begin to fabricate Cell processors with the 45 nm process. In May 2008, IBM introduced the high-performance double-precision floating-point version of the Cell processor,

7743-627: The top 6 "greenest" systems in the Green500 list, with highest MFLOPS/Watt ratio supercomputers in the world. Beside the QS22 and supercomputers, the PowerXCell processor is also available as an accelerator on a PCI Express card and is used as the core processor in the QPACE project. Since the PowerXCell 8i removed the RAMBUS memory interface, and added significantly larger DDR2 interfaces and enhanced SPEs,

7832-463: The use of numerical libraries to access code written in languages like C and Fortran , which perform math computations faster than newer languages like C# . Intel's MKL and AMD's ACML are written in these native languages and take advantage of multi-core processing. Balancing the application workload across processors can be problematic, especially if they have different performance characteristics. There are different conceptual models to deal with

7921-488: Was specifically designed for double-precision, reaches 102.4 GFLOPS in double-precision calculations. Tests by IBM show that the SPEs can reach 98% of their theoretical peak performance running optimized parallel matrix multiplication. Toshiba has developed a co-processor powered by four SPEs, but no PPE, called the SpursEngine designed to accelerate 3D and movie effects in consumer electronics. Each SPE has

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