ARM: Considering the balance between power consumption and performance, the quad-core architecture is still the limit of mobile phones at this stage.

ARM held a small media gathering last weekend. Some media asked that the current multi-core architecture of smartphones is still capped at 4 cores (note: even the big and small cores are 4+4 dual Group switching does not allow 8 cores to be executed at the same time). Is it possible to exceed this limit in the future? ARM’s answer is that in addition to the current multi-core design of ARM, which is still up to 4 cores, the theory of multi-core architecture will increase the energy consumption after exceeding 4 cores. The performance improvement is not ideal, so 4 cores will still be the limit of mobile phones in the short term.

Supplement: When the software support matures in the future, the large and small core architecture will allow two groups to perform the same task at the same time, but the software support is not yet perfect at this stage.

The most important thing last week was the sharing of trend predictions for the recent mobile phone market

ARM proposed trend predictions in four aspects; in terms of high-end mobile phones, large and small core technologies will It is the next mainstream architecture, and 2.5K resolution display support will also be a new battlefield for high-end mobile phones. In addition, GPU collaborative computing will also bring more applications to high-end mobile phones. As for mainstream and entry-level mobile phones, single-core will gradually fade out of the market starting this year. Dual-core or even quad-core will be the next mainstream, but it will not necessarily use the latest Cortex-A15, but Cortex-A9 and Cortex-A7. Lord.

In addition, the market is also looking for the third force in smartphone systems. Currently, Android and iOS alone account for 80% of the smartphone market. However, many manufacturers are not willing to be controlled by Google, so the third largest system The emergence of it has become a new topic, currently including Microsoft Windows Phone targeting the mid-to-high-end market, FirefoxOS for the entry-level market that emphasizes low hardware requirements, and ChinaOS based on Ubuntu from China, all of which are eyeing it.

Finally, there is the further evolution of wireless technology. It is expected that LTE’s market share will continue to expand in the next two years, so the market demand for LTE baseband technology will increase; In addition, starting from 802.11ac, WiFi technology will enter the Gb level transmission speed. In addition to bringing higher bandwidth to mobile phones, the data management of WiFi chips also requires stronger computing power; other wireless technologies including Bluetooth 4.0 and 4.0LE are gradually introduced into mobile phones. , and the NFC market will also grow significantly.

Regarding big.Little small and large core technology, the author has two articles discussing the characteristics of this architecture, so if you are interested, you can refer to: technical version, simple and easy-to-understand version. To put it bluntly, the purpose of introducing large and small cores is to improve the power consumption and performance ratio. According to ARM statistics, the average user uses a smartphone about 70% of the time with a very low load. However, the Cortex-A15 is designed for high-performance computing, so in this 70% time % of applications use the power-saving Cortex-A7, which can achieve a balance of performance and energy consumption.

Although the introduction of a large and small core architecture cannot save power as much as a pure Cortex-A7, in the information disclosed by ARM, the simulation is generally done under a 4-core architecture (the large and small cores are 4+4). In the usage environment, if the performance and power consumption of Cortex-A7 are both regarded as 1, and when using Cortex-A15 alone, although it has up to 2.5 times the computing power, the energy consumption will also increase by nearly 4 times, but if The performance of large and small cores is also 2.5 times, but the power consumption only increases by 2 times.

Although the large and small core architecture cannot control the power consumption to the same level as the pure Cortex-A7, it can still improve the performance and use lower power consumption to achieve the same performance. This is the new big and small core architecture. The best value among mobile phones of this generation. ARM also expects that large and small cores will become the main technology of many partners in the future, and may even be popularized in mid-range mobile phone chips in 2014.

Moreover, the large and small cores are a highly liberalized architecture. Manufacturers can configure different solutions according to performance requirements. For example, Samsung's Exynos5Octa uses a 4+4 architecture, but it also allows a 1+4 design for one large core and four small cores. , or a 2+2 design of two large and two small; and the large and small core architecture is not only favored in mobile phones, but also chip designers including servers, set-top boxes, and digital TVs have noticed that this architecture provides excellent performance in the standby state of electronic products. power management capabilities.

As for GPU cooperative computing, which was regarded as a high-performance computing level in the past, it is gradually sprouting in mobile phones, and therefore the performance of GPU will be increasingly valued in smart phones; for example, the Apple A6 application processor of iPhone5, wafer The area of ??the PowerVR GPU is much larger than the area occupied by the CPU. In addition to being used for game performance and image display, it is also widely used in camera photography functions.

The GPU can perform real-time HDR exposure rendering of a single photo on a mobile phone, portrait and object recognition, object tracking when taking pictures, as well as image coding calculation assistance, AR augmented reality applications, etc.; Many GPU collaborative applications have been supported by mobile phone manufacturers and system vendors. Consumers who purchase a new generation of mid-to-high-end mobile phones have already been enjoying the benefits of GPU parallel computing without knowing it.

In terms of ARM’s market share, the mobile phone hardware chip market is almost covered by ARM, and in smart phones, at least 3-5 chips based on the ARM architecture will be used, and many chips use There is not just one architecture; in addition to the Cortex-A and MaliGPU in the application processor, including telecommunications baseband management chips, wireless network management, I/O management, touch management, etc., ARM's Cortex- R real-time computing core and Cortex-M industrial control core architecture.

The Cortex-R core, originally used for real-time, high-performance management, will become increasingly important in chips in mobile phones in the future, especially when large amounts of data bandwidth traffic need to be managed. Wireless technologies that require increasingly shorter response times, such as LTE and 802.11ac, are driving the demand for Cortex-R architecture wireless chips for mobile phones.