Just talking about the number of cores doesn't make sense to bring you back to the phone Soc

How many cores do you have on your phone? This is one of our most frequently asked questions when comparing the two phone differences. The number of CPU cores is indeed an important indicator of the performance of a mobile phone, but it is not the most accurate indicator.

Take the most common Qualcomm Snapdragon in the market, for example, in the entire "processor", the CPU portion only accounted for 15% of the chip area, the other 85% is the image Processor (GPU), Digital signal Processor (DSP), modem, navigation positioning, multimedia and other chips or modules occupy.

In fact, compared to the "processor", we call this chip "SoC (System on chip, systems on chip)" more appropriate. The SOC is a tiny system, and if the CPU is likened to the brain, then the SOC is the entire human body, including the brain, Heart, eyes, and hands.

　　CPU: The brain of a cell phone

If the SOC is compared to the human body, the CPU is the entire SOC's brain. The official name of CPU is "CPU", you ask a friend "your phone is a few cores?" "This is the part that is meant to be. CPU is an ultra-large-scale integrated circuit, is also the core of the mobile phone operation and control, it occupies a small proportion of the area, but the most important function.

At work, the CPU is mainly responsible for the mobile phone general task processing and control, arbitration work. How much is the sum of operation A and operation B equal? Program C has a section of instructions to execute, need a few cycles? What do you do next after you've finished? These things CPU a second to "think" trillion times, make sure that your phone is always "smart".

The most frequently asked phrase is "How many cores do you have on your phone?" "refers to the number of CPU cores. Modern CPUs have long been out of the single-fight era, the integration of many processors into a chip, so that each processor in parallel to perform different tasks, improve processor speed, this is the basic idea of modern multi-core processor. The current mobile phone processor has dual-core, quad-core, eight-core and many other forms.

The number of cores can reflect performance to some extent, but things are not so absolute, in addition to the core number, the individual core itself "quality" is also very important, which involves another concept: architecture, caching, frequency.

In general, the smartphone CPUs you can buy today use the same instruction set--armv7-a developed by ARM, and you can understand that different CPUs speak the same language (Mandarin). But under the same instruction set, ARM offers a variety of different architectures for manufacturers to choose from (everyone speaks Mandarin, also divided into elementary students, middle school students, college students), such as Common Cortex-a7, cortex-a9, cortex-a15 .... Such a powerful manufacturer as Qualcomm, It will also develop its own unique architecture, such as the "krait" used by the Dragon 800/600/400 series processors.

Different architectures have different performance and power consumption, in order to specifically understand the differences between the various architectures, the length of this article is precarious, here is not much to say. You just need to know: The CPU is only a small part of the entire SOC, the number of cores is a small percentage of CPU performance indicators, the number of cores does not represent the final performance of the CPU, and not the performance of the entire Soc.

By the same measure, there is another important indicator of mobile CPU-energy consumption. Cell phone battery capacity is limited, power saving is a required course for each CPU, many companies in this area have their own skills. For example, in the Dragon processor, Qualcomm's self-developed ASMP architecture allows individual control of each processor core voltage and frequency, when the task is relatively simple, the processor will also be intelligent into the sleep state, the final manifestation of the effect is fast and power-saving.

　　GPU: An ultra-fast painter

What mobile games do you usually play? is the intellectual type of "Monument Valley", the stimulation of "tower defense" is the picture-realistic "real car"? In fact, whether it is 2D or 3D games, they are more or less with the mobile phone GPU inseparable from the relationship. Which parts occupy the largest area of the phone Soc? To tell you, it is also the GPU (Graphic processing Unit, image Processing Unit), GPU is responsible for most of the graphics on the phone rendering, your usual play of those mobile games, most of which are processed by it, you can think of it as an ultra-fast paint artist.

At first, the phone's GPU was a simple, unimportant component. Like Apple's first-generation iphone, some of Nokia's Symbian-based smartphones, their GPUs, are "pathetic" in terms of functionality and performance. But as technology developed, the GPU's position in the SOC expanded rapidly, even exceeding the CPU, occupying a large chunk of the site.

Why is the GPU becoming more and more important? Look at the bigger screen on your phone--the resolution has evolved from the earliest VGA (640x480) to the present 1080p (1920x1080) and even 2K (2560x1440), and the GPU needs to render dozens of times times more graphics pixels. Features and performance are naturally rising.

Yes, with the evolution of functionality and performance, the GPU can now do more than just graphics, and it even "steals" some of the CPU's work. Android system from 4.0 to 4.1 the famous "Butter Evolution" (Project Butter), is to let the GPU assume the system interface rendering work, so that the entire system interface becomes smoother, silky smooth.

GPUs are particularly well-suited for processing massively parallel data, because graphical computing is itself a massively parallel process. Now many of the graphics outside the Android system are given to the GPU, such as Web page rendering, the browsers that you think are very fast to use, the GPU is used to render the page in all likelihood.

In the future, with the expansion of reality and other virtual vision technology, the GPU will assume more general processing tasks, and its relationship with the CPU will be more subtle, with a word of the image point is: CPU management, GPU as labor. We expect the GPU to be a bullish position on the entire SOC, a good potential stock. The next time you have enough to buy a mobile phone, remember to focus on its GPU.

　　DSP: expert in data processing

Why are some phone cameras slow to use, and some phone cameras are lightning fast? In addition to the software optimization of the skill, mobile phone camera is still standing behind a hero--dsp.

DSP is another key processing component, which is somewhat similar in nature to the GPU: specialized in large-scale, parallel data, the most typical two examples are the images taken by the phone camera, and the variety of sound effects in the mobile phone player.

Do not underestimate the two seemingly simple tasks, now mobile phone camera pixels are high and frightening, continuous shooting speed 10fps, 20fps, if there is no DSP, a large number of image data in a short time enough to fill a quad-core CPU, so that your mobile phone completely can not do other things.

According to publicly available data, the most powerful mobile phone DSP on the market is from Qualcomm's upcoming Dragon 810 processor, which features a 14-bit dual-image signal processor with a hexagon DSP and a pixel throughput of up to 1.2gpixels/s--1.2 billion pixels per second! With this figure, you can feel how scary the amount of data flows through the DSP.

Thanks to the dedicated DSP, we can enjoy more and more pixels, 0 shutter delay, face detection and advanced post-processing such as object removal and cloning in the mobile camera. Unlike CPU and GPU, the task of DSP is more focused and single. DSP is not capable of the CPU, GPU all the task, but in its own good image, sound processing, it runs much lower than the CPU and GPU, so we call the DSP "Data processing experts."

　　Baseband/RF Front end: Phone's ears and mouth

After entering the 3g/4g era, as long as the mobile network is connected, it seems that any mobile phone can download a lot of pictures, watching high-definition video, but in the 2G era, things are not so simple. You can be so easy to brush Weibo, brush friends circle, online shopping ... it's all about the evolution of the handset baseband chip and RF front end. If the cell phone compared to the human body, integrated mobile phone SOC inside the baseband chip, coupled with an external RF front end, is the human ear and mouth, they are responsible for mobile phone and the outside world communication.

Baseband chip, also known as baseband, its most important function is to modulate the transceiver signal. Specifically, when you call someone, the baseband chip compiles your voice signal into the baseband code that is used to transmit it to the base station, and when someone calls you, the baseband chip interprets the baseband code received as an audio signal and then sends it through the speaker. In the 3g/4g era, baseband chips are also responsible for compiling large volumes of web pages, images, and video information--and for baseband chips, these things will eventually become signals.

Because the process of modulating the signal is too complex, the baseband chip is like a small kingdom of its own, it has its own CPU, its own channel encoder, its own DSP, its own modem and interface module ... the better baseband, such as Qualcomm's Gobi, also incorporates its own exclusive 256MB memory.

The module that works with the baseband chip is called the RF Front end (RF), which is responsible for the digital/analog conversion of the signal, while also responsible for amplifying the signal. Baseband chips and RF front-end work together to determine the phone's communication format. Is your phone 3G or 4G? can be compatible with Unicom, mobile or telecom networks? These are the baseband chip + RF front-end to decide.

In addition to supporting a wide range of communication formats, the excellent baseband chip must also have the ability to "mix" the different bands, because the spectrum resources of different operators are too scattered. For example, China Mobile 4G Network has a total of 130MHz of spectrum resources, the frequency band is scattered into three, respectively: 1880-1900mhz, 2320-2370mhz, 2575-2635mhz. When the cell phone is working, the communication module has to combine the three different bands to simulate "one band" for communication, so that we can guarantee the fastest speed, we call this function "carrier aggregation". For example, the carrier polymerization technique is the equivalent of a valve that puts a lot of small, scattered water pipes together and eventually forms a large, abundant stream.

In addition, the new generation of mobile phones is also a trend: to all the signal-related parts of the baseband chip to manage. such as GPU signal, WiFi signal, Bluetooth signal ... in the past, the mobile phone each add such a connection function, you need to install a chip. Now they are handed to the base to bring the tube, you can save a lot of costs, power consumption will be greatly reduced.

The baseband chip is also known as "the toughest design area on the phone" due to its ultra-high functionality and complexity. Qualcomm's ace combination--gobi baseband chip + RF360 RF Front-end is the industry benchmark, it functions like Superman: The most top with Gobi can support Gsm/wcdma/cdma/tdd-lte/fdd-lte and other 2G to 4G of all network formats , compatible with up to dozens of different frequency bands of global operators, can integrate dispersed frequency bands through carrier aggregation technology, and can send and receive a wide range of signals such as wifi/Bluetooth/GPS/FM radios; To save power, each module can be individually switched .... And, most incredible of all, Such a powerful baseband chip can also be made with silicon semiconductor process, as a module integrated into the SOC! This is in fact the Qualcomm company in the industry a major technical advantage.

How to determine the technical level of baseband chip in a mobile phone soc? You don't have to force yourself to memorize obscure technical terms, just look at its features--how many 4G formats are supported? How many network bands are compatible? Support does not support WiFi 802.11ac? Using the exclusion method one by one filter, you will find that the final selection is left out.

　　Multimedia engine: The Cinema in the pocket

Two or three years ago, to play 1080p Blu-ray movies, you also dedicated money to buy a Blu-ray player. Now, you just have to take out your phone and tap the screen to play high-quality 1080p video, isn't it amazing?

This is normal, because you have a powerful multimedia engine on your phone's SOC that already has all the video codec jobs.

Fluent decoding 1080p resolution of the H. S video is the standard configuration of a new generation of mobile phone soc, you do not have to worry about the bit rate, resolution problem, these are the credit of the multimedia engine.

With the new generation of SoCs represented by Dragon 805/Dragon 810, the built-in multimedia engine even started to support next-generation h.265 (HEVC) hardware decoding, which is enough to decode 4K resolution video at a maximum of 60Hz frame rate, so powerful parameters can not help people sigh: mobile phone screen to keep up?

　　Sensor Center: Always on standby green Butler

Remember the "M7 coprocessor" that Apple advertised at the launch of the iphone 5s? When the main processor (CPU) remains dormant, it can replace some low-volume, long-running tasks, greatly reducing the power consumption of the entire Soc.

When Moto X was released, Motorola demonstrated a magical feature: The phone stays dormant, and if you say a word, you can wake it up in an instant. Now, many phones already have such a feature.

The new generation of mobile SoCs integrates modules that specifically support sensor operations, such as Samsung, which calls similar modules on the Galaxy S5 "sensor hub". When you sigh the magic of Moto X phone Voice awakening, don't forget that there is a sensor center in your phone SOC that supports silently behind.

　　Power Management: Energy-saving explorer

Processor to save power, scientific power management of course. The power management here is not the free software downloaded on Google Play, but the actual hardware circuitry, which is integrated into the chip and is part of the Soc.

Taking Qualcomm Snapdragon as an example, when working on the SOC, the power management circuit controls each CPU core, which dynamically adjusts the frequency and voltage of each CPU core according to the task load, saving power to a minimum. At the same time, Dragon's power management power also supports Qualcomm Quick charge, a fast charging technology that can shorten the charging time by up to 75%.

　　Conclusion

In the past, when we talked about mobile phone processor performance, we were always too focused on the CPU itself, ignoring the other components, which is obviously unreasonable. In fact, we should look at the phone "processor" in a more scientific light-it's a SOC, a system that contains a large number of different components that work together. Unlike a computer, a phone is not only an arithmetic tool, but also your phone, Walkman, camera, and game console. In the phone SOC, there are twenty or thirty different components that work for you, in addition to the CPU, and they are important partners you should focus on.

Just talking about the number of cores doesn't make sense to bring you back to the phone Soc