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Intel Turbo Boost Technology
INTRODUCTION
INTEL TURBO BOOST TECHNOLOGY is the fascinating technology which automatically provides performance on demand. Intel Turbo Boost Technology is one of the many exciting features that Intel has built into latest-generation Intel microarchitechture codename Nehalem processor cores to run faster than the base operating frequency if it's operating below power, current, and temperature specification limits. Intel Turbo Boost technology, as the name suggests, helps boost the performance of your computer's multi-core processor. The program, in its most simple terms, operates by increasing the speed of each core on a system's chipset, drawing power away from parts of the CPU not currently being used while providing that extra power to the chip's active processors.
Basically, if the current application workload isn't keeping all four cores fully busy and pushing right up against the chip's TDP (Thermal Design Power) limit, Turbo Boost can increase the clock speed of each core individually to get more performance out of the chip.
It's easy to see how this works when just one or two cores are being actively used; whatever power the other two or three cores would have consumed can be redirected over to the active cores, allowing them to run at higher speeds. Basically, if the current application workload isn't keeping all four cores fully busy and pushing right up against the chip's TDP (Thermal Design Power) limit, Turbo Boost can increase the clock speed of each core individually to get more performance out of the chip.
It's easy to see how this works when just one or two cores are being actively used; whatever power the other two or three cores would have consumed can be redirected over to the active cores, allowing them to run at higher speeds.
The quad-core mode of Turbo Boost is a little more subtle; it works when the four cores aren't running a worst-case workload--for example, integer-heavy processing, since it's generally floating-point calculations that consume the most power--so they aren't bumping into the TDP limit. Turbo Boost can increase the frequency of all four cores until they're running as fast as they can for the current workload.
MICROPROCESSOR
The microprocessor is one of the important components of a digital computer. It acts as the brain of the computer system. Before going to the detailed description of the microprocessor, let us see what a digital computer is. A digital computer makes processing of numbers.
Computers are the most powerful tool man has ever created. A digital computer is a programmable machine. Its main components are: cpu, memory, input device and output device. The schematic diagram of a digital computer is shown below:
Schematic diagram of a digital computer
The CPU executes the instructions. The input device is used to feed programs and data to the computer. The memory is a storage device. It stores programs, data and result. The output device displays or prints the data or results according to the instruction given to the computer. The central processing unit built into a single IC is called microprocessor. A digital computer in which only one microprocessor has been built to act as the CPU is called the microcomputer. A desktop computer and portable computers like laptop, notebook, palmtop, etc. contain one microprocessor to act as the CPU and hence they come under the category of microcomputer.
MULTICORE PROCESSOR
In computing, a processor is the unit that reads and executes program instructions, which are fixed-length (typically 32 or 64 bit) or variable-length chunks of data. The data in the instruction tells the processor what to do. The instructions are very basic things like reading data from memory or sending data to the user display, but they are processed so rapidly that we experience the results as the smooth operation of a program.
Processors were originally developed with only one core. The core is the part of the processor that actually performs the reading and executing of the instruction. Single-core processors can only process one instruction at a time. (To improve efficiency, processors commonly utilize pipelines internally, which allow several instructions to be processed together, however they are still consumed into the pipeline one at a time.)
A multi-core processor is a processing system composed of two or more independent cores. One can describe it as an integrated circuit to which two or more individual processors (called cores in this sense) have been attached.[1] Manufacturers typically integrate the cores onto a single integrated circuit die (known as a chip multiprocessor or CMP), or onto multiple dies in a single chip package. A many-core processor is one in which the number of cores is large enough that traditional multi-processor techniques are no longer efficient — this threshold is somewhere in the range of several tens of cores — and probably requires a network on chip.
A dual-core processor contains two cores, a quad-core processor contains four cores, and a hex-core processor contains six cores. A multi-core processor implements multiprocessing in a single physical package. Designers may couple cores in a multi-core device together 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 to interconnect cores include bus, ring, 2-dimensional mesh, and crossbar. Homogeneous multi-core systems include only identical cores, unlike heterogeneous multi-core systems. Just as with single-processor systems, cores in multi-core systems may implement architectures like superscalar, VLIW, vector processing, SIMD, or multithreading.
Multi-core processors are widely used across many application domains including general-purpose, embedded, network, digital signal processing (DSP), and graphics.
The amount of performance gained by the use of a multi-core processor depends very much on the software algorithms and implementation. In particular, the possible gains are limited by the fraction of the software that can be parallelized to run on multiple cores simultaneously; this effect 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 beyond even that if the problem is split up enough to fit within each processor's or core's cache(s) due to the fact that the much slower main memory system is avoided. Many typical applications, however, do not realize such large speedup factors. The parallelization of software is a significant on-going topic of research.
Advantages
The proximity of multiple CPU cores on the same die allows the cache coherency circuitry to operate at a much higher clock-rate than 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 a given time period, since individual signals can be shorter and do not need to be repeated as often.
The largest boost in performance will likely be noticed in improved response-time while running CPU-intensive processes, like antivirus scans, ripping/burning media (requiring file conversion), or searching for folders. For example, if the automatic virus-scan runs while a movie is being watched, the application running the movie is far less likely to be starved of processor power, as the antivirus program will be assigned to a different processor core than the one running the movie playback.
Assuming that the die can fit into the package, physically, the 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 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.
Disadvantages
Maximizing the utilization of the computing resources provided by multi-core processors requires adjustments both to 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. The situation is improving: for example the Valve Corporation's Source engine offers multi-core support, and Crytek has developed similar technologies for CryEngine , which powers their game, Crysis. Emergent Game Technologies Gamebryo engine includes their Floodgate technology which simplifies multicore development across game platforms. In addition, Apple Inc.'s latest OS, Snow Leopard has a built-in multi-core facility called Grand Central Dispatch for Intel CPUs.
Integration of a multi-core chip drives chip production yields down and they are more difficult to manage thermally than lower-density single-chip designs. Intel has partially countered this first problem by creating its quad-core designs by combining two dual-cores on 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. 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 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. If a single core is close to being memory-bandwidth limited, going to dual-core might only give 30% to 70% improvement. If memory bandwidth is not a problem, a 90% improvement can be expected. It would be possible for an application that used two CPUs to end up running faster on one dual-core if communication between the CPUs was the limiting factor, which would count as more than 100% improvement.