21-04-2011, 03:39 PM
toseef Dual-core Processors.doc (Size: 206 KB / Downloads: 56)
1. Introduction
A dual-core processor is a CPU with two separate cores on the same die, each with its own cache. It’s the equivalent of getting two microprocessors in one. In a single-core or traditional processor the CPU is fed strings of instructions it must order, execute, then selectively store in its cache for quick retrieval. When data outside the cache is required, it is retrieved through the system bus from random access memory (RAM) or from storage devices. Accessing these slows down performance to the maximum speed the bus, RAM or storage device will allow, which is far slower than the speed of the CPU. The situation is compounded when multi-tasking. In this case the processor must switch back and forth between two or more sets of data streams and programs. CPU resources are depleted and performance suffers.
In a dual-core processor each core handles incoming data strings simultaneously to improve efficiency. Just as two heads are better than one, so are two hands. Now when one is executing the other can be accessing the system bus or executing its own code. Adding to this favorable scenario, both AMD and Intel’s dual--core flagships are 64-bit.
A dual-core processor is different from a multi-processor system. In the latter there are two separate CPUs with their own resources. In the former, resources are shared and the cores reside on the same chip. A multi-processor system is faster than a system with a dual-core processor, while a dual-core system is faster than a single-core system, all else being equal.
An attractive value of dual-core processors is that they do not require a new motherboard, but can be used in existing boards that feature the correct socket. Servers running multiple dual-core processors will see an appreciable increase in performance.
Multi-core processors are the goal and as technology shrinks, there is more “real-estate” available on the die. In the fall of 2004 Bill Siu of Intel predicted that current accommodating motherboards would be here to stay until 4-core CPUs eventually force a changeover to incorporate a new memory controller that will be required for handling 4 or more cores.
1.1 Implications for the Enterprise
The corporate computing environment has witnessed dramatic changes in the last few years, with a shift from rapid expansion of IT infrastructure in support of growing business needs, to carefully managing existing assets and investing in new strategic technologies that provide specific competitive advantages. Information technology (IT) managers today are challenged with providing more services to more users, meeting ever-increasing performance expectations, storing and managing exponentially increasing amounts of data, better protecting the network, and ensuring system stability—all with limited possibility to expand data centers because of shrinking budgets.
Key drivers for multi-core processors in Server/Workstation environments include:
• Reliance on x86 architecture as the backbone of corporate IT networks is placing performance demands on today’s servers to run a growing list of complex applications.
• Data centers’ performance requirements are growing while at the same time budget and logistical concerns deter physical expansion within many enterprises. Methods such as server consolidation and virtualization to better utilize existing resources have become appealing options to curtail costs.
• Multi-threaded applications are expected to be adopted more broadly in the future. The need for multi-processor systems is growing in new areas.
• Security has become a critical issue, requiring new classes of software applications and technologies that are uniquely served by multi-core processors. An increasingly effective approach to providing additional platform security is to leverage the power of virtualization technology to segregate trusted applications from nontrusted ones.
• Increased performance without increased power consumption is a critical need. Corporate IT managers also remain resolute in their need to add performance without increasing the physical footprint for hardware. Multi-core processor solutions address these needs by providing increased performance without increasing power or physical space requirements.
• End-customers are demanding more capable systems with more capable processors
2. Which processors are dual core processors?
When shopping for a computer one thing that always stands out on the info sheet is the processor. Chances are it is manufactured by Intel or AMD. You see various models from the Pentium to the Athlon to the Celeron, to the Core 2 Duo. What’s the difference in all of those brands and how do you know which one is a dual core? Well with the ever constantly changing world of computers, the list I am going to give you now will most likely be outdated within a few months, but regardless I’ll give it a shot.
Note – This list does not contain every processor known, just the most popular consumer products that you are most likely to see when shopping around).
Single Core Processors:
Intel Celeron (Entry Level)
AMD Sempron (Entry Level)
Intel Pentium 4 (Probably the most well-known single core processor ever)
AMD Athlon (Considered by many to be the best single core processor on the market)
Dual Core Processors:
Intel Pentium D
AMD Athlon X2
Intel Core 2 Duo (Considered by most to be the best dual core processor on the market)
AMD Athlon FX
AMD Turion X2 (For laptops)
Intel Centrino Duo (For laptops)
Each of the above processors comes in multiple speeds and models. There are also the Core 2 Extremes and other processors made for high end gamers and computer enthusiast.
One thing you will almost always see is the GHZ speed or Gigahertz speed of the processor. I will admit it; anymore today the GHZ speed of a processor is mostly a gimmick to help sell the processor. While in the past (prior to 2003) the GHZ speed was important to determine how fast and how well the processor would work, today the speed is not nearly as important has how much information the processor can handle at once. This is usually measured in the form of the L2 cache and other geek terms. But without a standardized way of measuring a processors ability in simple terms that the average consumer can understand, we are all still stuck with displaying the obsolete GHZ speed. However that may actually be changing very soon.
While for the past few years the GHZ speeds really didn’t matter, Intel and AMD are both attempting to push their new model processors as far as they can, thus increasing the GHZ speeds enough so that it actually does make a bit of a difference. However these new processors won’t really be available until Q4 07 at the earliest. As it is, for top of the line processors like the Core 2 Duo and the Athlon FX, Ghz speeds are usually a lot slower, usually in the 1.8 to 2.8 Ghz range. This is because to push them any faster would require much more power and thus generate a lot more heat causing the system to actually run slower (because heat is not a good friend of a computer or electronics in general).
Before I leave you I should also note that geek circles are now all buzzing about Quad Core. Yup you guessed it, 4 microprocessors on one dye. It’s basically the same thing as dual core but with more microprocessors.
3.AMD multi-core
In August 2004, AMD was the first x86 processor manufacturer to demonstrate a fully functioning dual--core processor on a shipping platform. Although performance will vary based on the software application, corporate IT systems currently optimized for symmetrical multiprocessing (SMP) multi-threaded applications should see significant performance increases by using AMD multi-core processors. They are also inherently more capable of leveraging the benefits of multi-threaded applications because they are, essentially multi-processor systems reduced down to single chips. Multi-core processors, whether installed in desktops, notebook PCs, workstations or servers, can play a significant role in enabling companies to deploy sophisticated new security and virtualization layers.
3.1 Servers
Multi-core AMD Opteron processors provide the best performance per watt for servers, and will enable hardware manufacturers to increase the processing capacity of their “rack able” server products—including their server blade designs that share common network, power, and cooling components. AMD’s enterprise customers can deploy new server blade systems without having to increase the physical footprint of their computer system resources, plan for additional heat dissipation, or provide additional power. Multi-core processor-based servers will deliver more overall performance than those powered by single-core processors; while at the same time will be easier to manage because more processing capacity can be concentrated into fewer servers. For the same reason, multi-core servers will be less costly to operate.
3.2 Security
Viruses, worms, and spy ware are constantly testing firewalls and other network protection measures, and can wreak havoc on computer systems. As a result, software and hardware designers have been collaborating to provide better security options. AMD pioneered Enhanced Virus Protection (EVP) technology that provides protection at the platform level when used in combination with Microsoft Windows and the leading Linux distributions from SuSE and Red Hat. Available on all AMD64 processors, EVP is an important step to help users defend against some of the most common and damaging threats. AMD engineers continue to focus on ways to strengthen security, and have gone beyond EVP with multi-core AMD processors. Not only will systems powered by these processors be platform-protected from specific viruses when used as discussed above, but also AMD is bringing additional security features to all of its processors with a technology called Presidio. AMD multi-core processors using Presidio technology, coupled with appropriate operating system support, will be able to run more Sophisticated security applications by better leveraging Direct Connect Architecture and virtualization technologies to provide increased performance capacity.
3.3 Virtualization
The use of software to allow workloads to be shared at the processor level by providing the illusion of multiple processors—is growing in popularity. Virtualization balances workloads between underused IT assets, minimizing the requirement to have performance overhead held in reserve for peak situations and the need to manage unnecessary hardware. AMD multi-core processors are well suited to help companies implement virtualization because they offer the increased performance necessary to counter performance penalties. The architecture of AMD multi-core processors offers a critical advantage when building “virtual machines” by leveraging Direct Connect Architecture to deliver very high-performance memory-sharing between virtual machines hosted on multiple cores within a single processor.