Qualcomm Logo San Diego AH-25

Qualcomm’s Heterogeneous Computing For Snapdragon 820

September 2, 2015 - Written By David Steele

The Snapdragon 820 is an important product for Qualcomm for a few reasons. The first is that the 820 introduces Qualcomm’s new custom core, the Kyro. Qualcomm have dispensed with the big.LITTLE architecture of their first generation of 64-bit high end processor, the Snapdragon 810, and instead the 820 is based around a single tier of processor cores. The new chip also introduces some new features, such as Qualcomm’s Smart Protect, which is a means of the processor core assessing the tasks that device applications are requesting of it and in essence, “sanity testing” these. If the Snapdragon 820 detects an untowards behaviour that could be as a result of malware on the device, it will notify the user – plus Qualcomm are also developing ties with malware developers to built a feedback mechanism.

Qualcomm have today written about one of the important refinements built into the Snapdragon 820’s architecture: heterogeneous computing. This means it gives the processor the ability to combine different components in order to maximize the power consumed by the system-on-chip. The Snapdragon 820’s heterogeneous processing abilities will combine application cores, graphics processor cores, digital signal processor cores and the Spectra camera ISP, all under the watchful eye of the Symphony System Manager. If this sounds familiar, readers may remember Motorola’s X8 processor, which powered the first Moto X smartphone released in 2013. The X8 consisted of two application cores, four graphics processor cores and two low power, context-aware cores that powered the always-on listening function of the smartphone and the Moto Display notification system. Qualcomm’s work with the Snapdragon 820 is reminiscent of Motorola’s approach, as here the Symphony System Manager is designed to divvy up the tasks demanding of the operating system and applications according to the resources available to it. This means that the Snapdragon 820 can devote the right processor core to the tasks at hand and sip battery and produce very little heat. It is a different set up to some competing system-on-chips, which may have more application cores available as a resource, but for certain duties plugging in an application core is a relatively inefficient use of resources.

The blend of computing tasks that will be made of the Snapdragon 820 – and Qualcomm’s other system-on-chips – is one reason why the company have invested a significant sum into building their custom core, the Kyro. The Kyro is tightly integrated with the Adreno GPU (version 530 for the Snapdragon 820) and the Hexagon 680 DSP (digital signal processor). Qualcomm explain that the reason for engineering the Kyro custom core is so that the device offers a blend of high performance combined with great power efficiency. When clocked at 2.2 GHz and built on a 14nm process, Qualcomm state that the Snapdragon 820 is twice as powerful as the Snapdragon 810 and also offers twice the power efficiency. This is an impressive claim: furthermore, because the 820 uses less power for a given workload, it also produces less heat, which is something of a Snapdragon 810 weakness.

Qualcomm’s performance claims for the Snapdragon are interesting when compared with their former flagship, but we will need to wait for the first devices to ship with the new processor and be tested before we can pass judgement. However, Qualcomm’s approach of refining and optimizing a system-on-chip’s resources differs from MediaTek’s approach, which is to provide a given design more processor cores spread out over different performance levels. Both solutions are technically impressive and it will be interesting to see how 2016’s flagship devices perform.