ARM has unveiled the Cortex-A7 MPCore processor, the most energy-efficient application class processor ARM has ever developed, and big.LITTLE processing - a flexible new approach that looks to redefine the traditional power and performance relationship. A single Cortex-A7 processor delivers 5x the energy-efficiency and is one fifth the size of the Cortex-A8 processor, while providing significantly greater performance. ARM says that the processor will enable a richer user experience in the sub-$100 entry level smartphones market.
According to ARM one of the most significant challenges today is how to create a System on Chip (SoC) that meets consumer demand for devices which offer both higher-performance and extended battery life. Big.LITTLE processing, enabled by the Cortex-A7, looks to meet this by pairing the best of the high-performance Cortex-A15 MPCore and ultra-efficient Cortex-A7 processors. Big.LITTLE processing allows devices to select the right processor for the right task, based on performance requirements. Importantly, this dynamic selection is transparent to the application software or middleware running on the processors.
ARM Partners supporting these technologies include Broadcom, Compal, Freescale, HiSilicon, LG Electronics, Linaro, OK Labs, QNX, Redbend, Samsung, Sprint, ST-Ericsson and Texas Instruments.
Mobile usage has changed significantly and consumers increasingly use their smartphones forhigh-performance tasks, such as web browsing, navigation and gaming, and less demanding ‘always on, always connected’ background tasks, such as voice calls, social networking and email services.
“As smartphones and tablets continue to evolve into users’ primary compute device, consumers are demanding performance as well as the always on, always connected service they expect. The challenge for our industry and the ARM ecosystem is how to deliver on this,” said Mike Inglis, Executive Vice President, Processor Division, ARM. “The introduction of Cortex-A7 and big.LITTLE addresses this challenge and extends ARM’s technology leadership by setting a new standard for energy-efficient processors and redefining the traditional power and performance relationship.”
The efficiency of the ARM architecture is the reason why ARM processors use less power and occupy a smaller footprint. The Cortex-A7 processor occupies less than 0.5mm2, using 28nm process technology. Used as a stand-alone processor, the Cortex-A7 will deliver sub-$100 entry level smartphones in the 2013-2014 timeframe with an equivalent level of processing performance to today’s $500 high-end smartphones.
Big.LITTLE processing combines two different, but compatible processors within the same SoC and allows the power management software to seamlessly select the right processor, or multiple processors, for the right task. The processors appear identical from an applications software perspective.
The ‘LITTLE’, lowest-power processor – in this case, the Cortex-A7 - runs the Operating System (OS) and applications for basic always-on, always connected tasks, such as social media and audio playback. The OS and apps can then be seamlessly migrated to the higher-performance processor as demands increase for high end tasks, such as navigation and gaming. The time for this migration is in the order of 20 microseconds. This flexible approach of choosing the right processor for the right job enables highly optimized processing which results in significant energy savings for common workloads.
The efficient switching of workloads between the two processors is supported by advanced ARM system IP, such as AMBA 4 ACE Coherency Extensions. This ensures full cache, I/O and processor-to-processor coherency between the Cortex-A15 and Cortex-A7, and across the complete system. Software and applications can therefore continue to run unhindered, and unnoticed by the user, as the tasks are rebalanced to provide the optimum big.LITTLE user experience.
Big.LITTLE power management software is developed by ARM ecosystem partners months ahead of silicon availability using ARM DS-5 tools and Fast Model virtual prototyping technology. The virtual platform, available now to lead partners, contains the Cortex-A15 and Cortex-A7 processors, as well as cache coherent interconnect System IP, allowing full system software development.
