Multi-Core Computing

Multi-core’s mainstream

The power consumed by a server over its lifetime is likely to cost as much as the server itself if energy costs continue to rise. This has led to the development of energy-efficient multi-core server processors says Neeraj Gandhi.

The face of the data center is changing and it is doing so at a breakneck pace. Bigger applications and processing needs are forcing businesses to arm their data centers with denser technologies such as blade servers, faster and efficient processors, high capacity storage devices and high-bandwidth routers and switches to transport traffic between the servers and the outside world. All this is being done to enable data centers to run applications which handle the core business and operational data of any organization today.

The massive influx of technologies is creating a complex data center that is costly to manage, consumes more power, and is putting a strain on the infrastructure. As per the US Environmental Protection Agency (EPA) which observed that data centers consumed 61 billion kilowatt-hours (kWh) in 2006; that’s roughly 1.6 percent of total US electricity consumption, or about $4.5 billion in electricity costs. Some large data centers draw as much energy as a small town. Assuming the trend continues, by 2011, the energy consumption by servers and data centers is expected to nearly double.

This astronomical increase in power consumption and the associated costs to cool servers in the data center is putting tremendous pressure not only on the equipment but on the overall revenue of the business as well. The cost of managing the IT infrastructure (largely servers in the data center) has become the largest and fastest growing component of overall IT spending for many organizations. In fact power and cooling are the two most serious issues troubling CIOs today. Escalating energy cost are only adding fuel to a fire that is already burning.

Arnab Roy, General Manager-Marketing, Sun Microsystems India Pvt Ltd., said, “With a billion people participating online today, the network consumes more than 100 billion kilowatts of electricity and costs businesses around $7.2 billion in utility bills annually. And since the power consumption of data centers doubled between 2000 and 2005, it is no surprise that 25 percent of the IT budget is consumed by energy costs alone.” Some analysts have said that infrastructure power usage will soon cost more than the hardware itself.

In this scenario, multi-core processors are doing their bit to bring down energy consumption in the data center.

The rationale for multi-core processors

As per Gartner, Inc the number of cores on a chip will double approximately every 18 months through 2015. This has led to the development of energy-efficient multi-core server processors. According to Vamsi Krishna, Senior Manager-Technical, AMD India, “Enterprises today face a diverse set of direct and indirect challenges, while considering power requirements for their data centers. Poorly designed servers are not power efficient and this results in the consumption of unwanted power leading to wastage of energy.”

According to Morgan Stanley, the energy used to power and cool today’s data centers represents 44 percent of a data center’s total cost of ownership; that’s a huge bill for a company of any size. Looking at the flipside, it can also be a huge source of savings. Jyothi Satyanathan, Vice President, Systems p, IBM India-South Asia added, “Data centers typically consume 15 times more energy per square foot and energy costs are at least 10 to 30 times that of a typical office building and, in some cases, maybe 100 times higher—that’s significant power consumption.”

Enterprises cannot control the rising cost of energy, as it is an external entity. However, they can control and conserve the power consumed in their data centers by choosing energy-efficient servers and components. It is here that multi-core server processors have a starring role offering, as they do, raw performance and lower power consumption. To achieve this, they are more efficient in simultaneous processing of multiple tasks. These processors have the potential to give data center hardware, as well as its energy savings—a substantial boost. Multi-core processors can improve system efficiency and application performance for systems running multiple applications at the same time, thereby increasing the overall efficiency of a data center.

“Organizations are looking at reducing the total cost of ownership. They are trying to balance their IT budget for driving new initiatives versus the bulk of their budget supporting maintenance and operations. Industry reports from Gartner, Inc said that approximately 70 percent of the budget is going towards maintenance and operations. There is a clear need to reduce these costs, and power and energy would be key areas that organizations need to focus upon,” said R Ravichandran, Director, Sales (South Asia), Intel Technology India Pvt. Ltd.

According to Calvin Nicholson, Marketing Manager, Server Technology Inc., the biggest concern in a data center is the cost to operate devices vis-à-vis the work taken out of them. He added, “The cost of installation, operations and maintenance are approaching the cost of the server. As power and cooling costs continue to rise, the situation will get worse,” he warned.

Data center energy costs are expected to increase as companies deploy a greater number of servers, which consume more power, and in the process, emit more heat that needs to be dissipated. “If the current rates of growth continue and data center efficiencies remained unchanged, data center electric bills and power requirements will double in less than ten years, and electricity bills will increase by an additional $200 to $300 million each year,” said Satyanathan.

“Now that the cost and availability of power is going up around the world and the cost of a server is approaching the cost to install and operate it for a year, companies are really starting to look at where they can save money and be more efficient,” added Nicholson.

Flavor of the season

Multi-core is certainly the flavor of the season with Xeon, Opteron, UltraSPARC T1 & T2 and Power all embracing this approach. The multi-core architectures of server vendors differ and it is difficult to say whose is the best because just the fact that a processor architecture is multi-core confers some advantages on it.

Servers consume a lot of energy, and at the same time a lot of energy is spent to cool a data center. This essentially means that for every watt of power consumed, another watt is being spent as overhead for cooling. According to Rajesh Dhar, Country Manager-ISS, Technology Solutions Group, HP India, “An ideal power situation in a data center should be that for every one kWh of power used not more than one kWh should be used to cool it. But in reality almost two to two-and-a-half kWh of power is being used for this purpose. The ideal ratio is 1:1.”

To address this problem, vendors are offering a portfolio of energy efficient products that deliver high-performance and sustainable computing solutions.

Intel’s quad-core Xeon processors operate at 50W (12.5 W per core) versus the single core Xeon processors that used to consume 110W. The energy-efficient quad-core Xeon 7300 series supports frequencies up to 2.93 GHz at 130 watts, several 80-watt processors and a 50-watt version optimized for four socket blades and high-density rack form factors with a frequency of 1.86 GHz. Ravichandran said, “Intel’s internal IT department did a consolidation of servers from single core to quad core and this has helped achieve 66 percent faster performance, 66 percent lower power consumption, 87 percent reduction in footprint and savings of approximately $6,000 for every eight servers consolidated into one.”

Sun Microsystems launched the UltraSPARC (US) T1 processor in November 2005 with eight cores; each core was capable of executing four threads—32 simultaneous threads in all. In August 2007 the company introduced the US T2 (Niagara II) that has eight cores and can handle 64 threads. It blends high performance and low power consumption with three functions on one piece of silicon: multi-threaded 10 GbE networking, crypto acceleration, and PCI-Express I/O expansion. Roy said, “The power consumed by the US T2 is less than 95 watts (nominal) i.e. less than two watts per thread.”

The IBM POWER6 processor is a 65-nm 64-bit, dual-core processor with 790 million transistors running at up to 4.7 GHz with eight megabytes of on chip Level 2 cache. “The p6 processor doubles the speed of the previous generation, the p5, while using nearly the same amount of electricity to run and cool it. This means that customers can use the new processor to either increase their performance by 100 percent or cut their power consumption virtually in half,” said Satyanathan.

AMD’s quad-core Opteron comes with features like PowerNow and CoolCore to can switch off computing cores when there is no work load for them to crunch. This even applies at the transistor level when they are not in use, which result in additional energy conservation. Krishna said, “With the Opteron quad-core we enhanced PowerNow with a feature called Independent Dynamic Core Technology. This technology goes a step further and allows each core to vary its frequency depending on the specific performance need of the applications running on it. This increased flexibility is designed to help reduce the power consumption and heat dissipation of quad-Core Opterons when compared to its dual-core predecessor.”

Market developments

According to Forrester Research, servers consume 30 percent or more of a large data center’s total electricity requirement. Servers also generate heat, the removal of which from the data center via HVAC systems consumes still more power. So microprocessor manufacturers are pursuing energy efficiency by incorporating multiple processors on a single chip (multi-core designs) and using advanced materials and manufacturing processes that reduce a chip’s power consumption.

Multi-core processing is a growing industry trend as single core processors are rapidly reaching the physical limits of possible complexity and speed. The huge growth of computing requirements and the need to manage bigger applications has also fuelled the need for such processors. Moreover, with data center energy costs on course to outweighing the cost of the elements inside a facility, CIOs have started realizing the magnitude of the problem.

“With the increased use of applications that require more power and the issues of energy conservation, there continues to be a growing need to consolidate data centers and implement server virtualization technologies. Multi-core processors seem to be the answer to this problem,” said Satyanathan.

“Organizations are adopting multi-core based servers. In the recent past companies such as L&T, Bajaj Allianz and UB have already deployed our quad-core Xeon servers keeping power problems in mind,” opined Ravichandran.

Today businesses around the world employ bigger applications and maintain larger databases. Along with the increased use of these applications comes an increase in the amount of power needed to support these applications.

A multi-core processor seems to be an apt solution to this problem.

Data centers equipped with multi-core processors fare better. These chips offer better performance-per-watt than single-core processors. Resource utilization being the biggest challenge in a data center, these processors helps in consolidating resources with better utilization than single-core processors. This is precisely why the industry is changing from single-core to dual-core and to quad-core and beyond.

neeraj.gandhi@expressindia.com