Texas Instruments sees ARM's Cortex A7 as an Android accelerator

CHIP VENDOR Texas Instruments (TI) said ARM's heterogeneous 'Big.little' architecture helps it accelerate Google's Android operating system.

TI, which designs the popular range of OMAP system-on-chip (SoC) processors found in many smartphones told The INQUIRER that ARM's newly unveiled Big.little architecture will help improve overall performance of the Android operating system.

Avner Goren, GM of OMAP Strategy at TI told The INQUIRER that ARM's Big.little architecture, which uses Cortex A7 and Cortex A15 cores, addresses a different need than that of multi-core processors made up of identical cores.

Goren said, "We have been using heterogeneous multi-cores since 2002, we always had an ARM CPU coupled to accelerators for video, graphics, DSPs, image processing. This [Big.little] doesn't change anything in this idea. On the contrary, it builds on this concept and it is another dimension. None of what was held here changes what we are doing in the rest of the system."

Goren continued by saying that Big.little is a natural progression from the multi-core, accelerator-aided processors of yesteryear. "What we have held today doesn't change the fact I would continue doing accelerators, DSPs, video accelerators and use [Cortex] M3s inside, but it changes what I'm doing on the high-level Android side."

When ARM's multi-core processors tipped up at Mobile World Congress earlier this year firms were banging on about it would be a golden age of power efficiency due to being able to run multiple cores at lower frequencies. Now less than a year later and with dual-core smartphones still having relatively poor battery life, it looks like that strategy has gone for a Burton. Goren admits that homogenous multi-core architectures do have a problem.

"Multicores give you scalability in a range, performance goes up and down within this range based on how many cores are active and what is the voltage level for these cores. On the other hand it has a floor, this floor is when you have one core running at the lowest voltage. What we have identified is a need for general processing power, meaning running Android, even at a lower [power] level," said Goren.

Goren said ARM's A7 processor will allow TI to ramp up the Cortex A15 core without hurting the 'idle' performance of the more frequently used Cortex A7 core.

TI and other chip vendors have used accelerators to optimise particular aspects of SoC for use cases such as video playback, but seemed to exclude the fact that optimisations for the underlying operating system would also come in handy.

While ARM's Cortex A7 isn't an Android specific chip, meaning it is a general purpose processor capable of running any code compiled for the architecture, the fact that its primary job in Android smartphones will be to take care of the OS leaving most of the heavy lifting to the Cortex A15 cores, effectively means that chip makers are viewing the Cortex A7 as an Android accelerator. µ