64-bit for the masses with Cortex-A35

It has been four years since the announcement of the ARMv8 instruction set, three years since the launch of the ARM Cortex-A57 and Cortex-A53 cores, and two years since the Apple A7 with its “Cyclone” core blew away any misunderstanding of 64-bit as being just for servers.

There is, however, still this idea that 64-bit is only for flagship mobile devices. That might be because outside of the Apple sequence of parts, many vendors have plowed into octacore SoCs with a big.LITTLE cluster of A57s and A53s. The February launch of the Cortex-A72 moves the bar even higher. HiSilicon just hit the ground with their Kirin 950 last week, with four 2.3 GHz Cortex-A72s holding the big side, and four 1.8 GHz A53s still on the LITTLE.

Remember when the Cortex-A9 was in every mobile phone? It seems like not so long ago. The ARM roadmap has transitioned to a much more precise strategy, sizing cores for specific applications and processes. One upgrade path emerged in 2014 with the Cortex-A17 (after the Cortex-A12 attempt), trying to move into higher performance areas without the expense of ARMv8. The low-end took shape earlier, with the Cortex-A5 in 2009 on 40nm and the Cortex-A7 in 2011 on 28nm, power and footprint optimized variants of ARMv7.

As Sehat Sutardia put it a few ARM TechCons ago, “Who wants a dumbphone?” With Android just about everywhere and able to scale across devices with newfound 64-bit support, an entirely different world opens up. It turns out that in spite of all the advertising and press, much of the real world does not revolve around the flagship phone.

Part of this is what we termed “Asian ARM Fusion” in our upcoming book. (We’re completing the Epilogue for “Mobile Unleashed” after ARM TechCon, then on to final edit and layout – you may have seen the cover design Daniel Nenni shared earlier.) While Apple, Qualcomm, and Samsung were exchanging fire between flagships, the rest of the pack – primarily Asian firms – was sailing toward more cost-effective chips for less expensive phones.

Those entry-level smartphone volumes turned out to be massive. While Apple makes a big deal out of record shipments of just over 230M phones in fiscal 2015 (year-end September), and rightly so, over 2B entry-level smartphones have shipped on Cortex-A5 and Cortex-A7 since their introduction. Both those cores are now a bit long in the tooth.

ARM and Gartner project 50% of smartphones shipped in 2015 will be ARMv8-A. More significantly, they expect the entry-level smartphone annual run rate to exceed 1B in 2020 – dwarfing the flagship opportunity, which is turning more and more to architectural licensing.

It should come as no surprise that ARM is reloading with a new core to replace the aging Cortex-A5 and Cortex-A7, and turning to ARMv8 and 64-bit to fill out the third tier. The ARM Cortex-A35 introduced this week targets 10% lower power and from 6 to 40% more performance compared to the Cortex-A7 in the same process. Compared to the Cortex-A53, the core is 25% smaller, and 32% lower power in the same process.

Full ARM press release:

New ARM Cortex-A35 Processor Extends ARMv8-A Architecture Deeper Into Embedded and Mobile Markets

ARM expects vendors – and I’ll venture a guess the Asian firms will lead the way – to have Cortex-A35 implementations by the end of 2016. This new, ultra-efficient line also is likely to find a lot of design wins in non-mobile parts, for example IoT gateways, and there could be spots in LTE modems.

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