ARM's new split chip architecture visions high performing ultra-efficient processors

The idea

Along with the recent announcement of the highly energy efficient application processor Cortex A7 MPCore, ARM Holdings also revealed a new type of split chip architecture dubbed as big.LITTLE processing for future mobile devices. The new type of architecture involves the presence of two different processors on the same chip. One of these processors would be used for resource heavy tasks such as gaming and navigation while the other one would be used for lightweight tasks such as voice calls and text messaging.

ARM's new split chip architecture

Brainchild

The smartphones, which are essentially pocket sized computers, work in a much smaller environment thus requiring efficient processors for minimizing the battery consumption without compromising on the quality of the output. In answer to this, ARM has come up with the big.LITTLE processing, which allows the combination of two very different but compatible processors on the same SoC (system-on-chip). Therefore, combining the bigger and powerful Cortex-A15 MPCore with the energy efficient Cortex-A7 processor on the same SoC, the mobile device would be able to manage the power consumption better. ARM, thus once more is ahead of its competitors in creating a more energy efficient chip architecture.

The making

The smartphone users today want a mobile device that is not only high on performance but also doesn't drain out the battery too quickly. Big.LITTLE processing seems to be the perfect answer to this at the moment. The new split chip architecture allows manufacturers to combine two different processors i.e. the Cortex A7 and A15 on a single chip. The A7, which is more energy efficient can take over the lighter tasks such as voice calling and text messaging while the A15 would take over when the user fires up applications which are resource heavy such as gaming, navigation or browsing. All this switching over from one processor to the other will happen internally in about 20 microseconds without the user even realizing of such a switch. Thus, the right processor will be used for the right job conserving the life of the battery.

What's new

Currently, the trend is to put in as much power as you can in a single processor. In such circumstances, using two different processors on a single chip seems like a completely new idea that will take some time to adjust to. To add to that the A7 processor is much smaller in size and uses a 28-nanometer chip fabrication process instead of the usual 45-nanometer. The smaller size of the A7 processor would have meant - reduced speed - but, ARM has modified it in such a way that it is quite powerful enough to run even a entry level smartphone on its own.

The big.LITTLE processing developed by ARM would allow the manufacturers to pair Cortex-A15 and Cortex-A7 processors on a single platform. The A7, which consumes less power, would handle lighter tasks such as voice calls, basic operating system activities and user interfaces. The high performance A15 processor would take up tasks such as gaming, navigation and web browsing that require more power. Thus, the effortless switch between the processors would extend the battery life of the smart phone by up to 70 percent.

What's refreshing

ARM is not the first one to come up with the split chip architecture; nVidia already has the Tegra series processor in the market. The nVidia Tegra integrates more than one specialized processors, built for handling different tasks on a single chip. When a certain processor is handling a task, the rest of the processors not in use are turned off thus, saving battery. ARM's big.LITTLE processing is based on a similar concept, but they are completely different by way of execution. While nVidia uses low power silicon process for its co processors, ARM's big.LITTLE processing makes use of a simple, energy-efficient processor A7, for handling basic tasks and a bigger and powerful processor A15 for heavy workloads.

Applications

The ARM chip architectures have already proved their worth in handling high performance tasks and power consumption when compared to the chipset from other companies such as Atom developed by Intel. In such circumstances, the combination of Cortex-A15 and Cortex-A7 processor on a single chip would open up doors for new possibilities in the mobile platform. Now it's all up to the manufacturers to use this new architecture for developing better smartphones.

By the year 2013 or 2014, you can also expect to see the standalone Cortex-A7 processor being used in the $100 category of the smartphones. This would mean even a basic smartphone would function no less than a high-end smartphone. While the A7 processor would power the entry level smartphones, the A15 processor would take the performance of the present day smartphones to a whole new level, where probably the battery wouldn't drain out so quickly.