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ARM’s secret recipe for power efficient processing

Posted by wicked November - 20 - 2014 - Thursday Comments Off
ARM SoC Fabrication Wafer Processor

There are several different companies that design microprocessors. There is Intel, AMD, Imagination (MIPS), and Oracle (Sun SPARC) to name a few. However, none of these companies is known exclusively for their power efficiency. That isn’t to say they don’t have designs aimed at power efficiency, but this isn’t their specialty. One company that does specialize in energy efficient processors is ARM.

While Intel might be making chips needed to break the next speed barrier, ARM has never designed a chip that doesn’t fit into a predefined energy budget. As a result, all of ARM’s designs are energy efficient and ideal for running in smartphones, tablets and other embedded devices. But what is ARM’s secret? What is the magic ingredient that helps ARM to produce continually  high performance processor designs with low power consumption?

A high-end i7 processor has a maximum TDP (Thermal Design Power) of 130 watts. The average ARM-based chip uses just two watts max budget for the multi-core CPU cluster, two watts for the GPU and maybe 0.5 watts for the MMU and the rest of the SoC!

In a nutshell, the ARM architecture. Based on RISC (Reduced Instruction Set Computing), the ARM architecture doesn’t need to carry a lot of the baggage that CISC (Complex Instruction Set Computing) processors include to perform their complex instructions. Although companies like Intel have invested heavily in the design of their processors so that today they include advanced superscalar instruction pipelines, all that logic means more transistors on the chip, more transistors means more energy usage. The performance of an Intel i7 chip is very impressive, but here is the thing, a high-end i7 processor has a maximum TDP (Thermal Design Power) of 130 watts. The highest performance ARM-based mobile chip consumes less than four watts, oftentimes much less.

This isn’t the world of desktops and big cooling fans, this is the world of ARM.

And this is why ARM is so special, it doesn’t try to create 130W processors, not even 60W or 20W. The company is only interested in designing low-power processors. Over the years, ARM has increased the performance of its processors by improving the micro-architecture design, but the target power budget has remained basically the same. In very general terms, you can breakdown the TDP of an ARM SoC (System on a Chip, which includes the CPU, the GPU and the MMU, etc.) as follows. Two watts max budget for the multi-core CPU cluster, two watts for the GPU and maybe 0.5 watts for the MMU and the rest of the SoC. If the CPU is a multi-core design, then each core will likely use between 600 to 750 milliwatts.

These are all very generalized numbers because each design that ARM has produced has different characteristics. ARM’s first Cortex-A processor was the Cortex-A8. It only worked in single-core configurations, but it is still a popular design and can be found in devices like the BeagleBone Black. Next came the Cortex-A9 processor, which brought speed improvements and the ability for dual-core and quad-core configurations. Then came the Cortex-A5 core, which was actually slower (per core) than the Cortex-A8 and A9 but used less power and was cheaper to make. It was specifically designed for low-end multi-core applications like entry-level smartphones.


At the other end of the performance scale, came the Cortex-A15 processor, it is ARM’s fastest 32-bit design. It was almost twice as fast as the Cortex-A9 processor but all that extra performance also meant it used a bit more power. In the race to 2.0Ghz and beyond many of ARM’s partners pushed the Cortex-A15 core design to its limits. As a result, the Cortex-A15 processor does have a bit of a reputation as being a battery killer. But, this is probably a little unfair. However to compensate for the Cortex-A15 processor’s higher power budget, ARM released the Cortex-A7 core and the big.LITTLE architecture.

The Cortex-A7 processor is slower than the Cortex-A9 processor but faster than the Cortex-A processor. However, it has a power budget akin to its low-end brothers. The Cortex-A7 core when combined with the Cortex-A15 in a big.LITTLE configuration allows a SoC to use the low-power Cortex-A7 core when it is performing simple tasks and switch to the Cortex-A15 core when some heavy lifting is needed. The result is a design, which conserves battery but yet offers peak performance.


ARM also has 64-bit processor designs. The Cortex-A53 is ARM’s power-saving 64-bit design. It won’t have record breaking performance, however it is ARM’s most efficient application processor ever. It is also the world’s smallest 64-bit processor.  Its bigger brother, the Cortex-A57, is a different beast. It is ARM’s most advanced design and has the highest single-thread performance of all of ARM’s Cortex processors. ARM’s partners will likely be releasing chips based on just the A53, just the A57, and using the two in a big.LITTLE combination.

ARM Cortex A50

One way ARM has managed this migration from 32-bit to 64-bit is that the processor has different modes, a 32-bit mode and a 64-bit mode. The processor can switch between these two modes on the fly, running 32-bit code when necessary and 64-bit code when necessary. This means that the silicon which decodes and starts to execute the 64-bit code is separate (although there is reuse to save area) from the 32-bit silicon. This means the 64-bit logic is isolated, clean and relatively simple. The 64-bit logic doesn’t need to try and understand 32-bit code and work out what is the best thing to do it each situation. That would require a more complex instruction decoder. Greater complexity in these areas generally means more energy is needed.

A very important aspect of ARM’s 64-bit processors is that they don’t use more power than their 32-bit counterparts. ARM has managed to go from 32-bit to 64-bit and yet stay within its self-imposed energy budget. In some scenarios the new range of 64-bit processors will actually be more energy efficient than previous generation 32-bit ARM processors. This is mainly due to the increase in the internal data width (from 32- to 64-bits) and the addition of extra internal registers in the ARMv8 architecture. The fact that a 64-bit core can perform certain tasks quicker means it can power-down quicker and hence save battery life.

ARM Cortex A57

This is where the software also plays a part. big.LITTLE processing technology relies on the operating system understanding that it is a heterogeneous processor. This means the OS needs to understand that some cores are slower than others. This generally hasn’t been the case with processor designs until now. If the OS wanted a task to be performed, it would just farm it out to any core, it didn’t matter (in general), as they all had the same level of performance. That isn’t so with big.LITTLE. Thanks to Linaro hosting and testing the  big.LITTLE MP scheduler, developed by ARM, for the Linux kernel which understands the heterogeneous nature of big.LITTLE processor configurations. In the future, this scheduler could be further optimized to take into account things like the current running temperature of a core or the operating voltages.

The future is looking brighter than ever for mobile computing.

There is also the possibility of more advanced big.LITTLE processor configurations. MediaTek has already proven that the big.LITTLE implementation doesn’t need to be adhered to rigidly. Its current 32-bit octa-core processors use eight Cortex-A7 cores, but split into two clusters. There is nothing to stop chip makers from trying other combinations that include different sizes of LITTLE cores in the big.LITTLE hw and sw infrastructure, effectively delivering big, little and eve smaller compute units. For example,  2 to 4 Cortex-A57 cores, tx performance tuned Cortex-A53 cores, and two smaller implementations of the Cortex-A53 CUP tuned towards lowest leakage and dynamic power – effectively resulting in a mix of 6 to 8 cores with 3 levels of performance.

ARM Cortex A50 BIG.litte

Think of the gears on a bicycle, more gears means greater granularity. The extra granularity allows the rider to pick the right gear for the right road. Continuing the analogy, the big and LITTLE cores are like the gears on the crank shaft, and the voltage level is like the gears on the back wheel – they work in tandem so the rider can choose the optimum performance level for the terrain.

The future is looking brighter than ever for mobile computing. ARM will continue to optimize and develop its CPUs around a fairly fixed power budget. Manufacturing processes are improving and innovations like big.LITTLE will continue to give us the benefits of peak performance with lower overall power consumption. This isn’t the world of desktops and big cooling fans, this is the world of ARM and its energy efficient architecture.

Nexus 4 Lollipop OTA Zip file now available to download and install

Posted by wicked November - 16 - 2014 - Sunday Comments Off


We saw the Lollipop factory image for the Nexus 4 (occam) land a couple of days ago, so we knew it was only a matter of time until the OTA Zip file was posted. Good news for this Sunday morning. It’s available right now for your downloading pleasure.

Updating via OTA route is preferred since you don’t have to worry about losing your data, assuming your device is locked. You should still backup your data however.

We have the download link below and be sure to check out our extensive guide on how to install this bad boy. You won’t find more detailed instructions anywhere else.

source: Nexus 4 (occam) From KTU84P to LRX21T

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Is Google Glass’ allure fading away?

Posted by wicked November - 15 - 2014 - Saturday Comments Off


Just months ago, Google opened up the purchase of Glass to the public, but for the insane price of $1,500. Of course, the units are meant for developers only, but one might question when the prototype will hit its final stage and get released to the mass market for an affordable price.

According to a recent report by Reuters, the allure of Glass is starting to wear off — a miserable, miserable sign for Google, especially since the public hasn’t even gotten its hands on a finished product.

Reuters contacted 16 Glass app makers — nine of the 16 said they had stopped or completely abandoned their project, because of the lack of customers or limitations on the device. It seems like a pretty obvious business decision — if there are no customers, why build something?

Little Guy Games Chief Executive Tom Frencel told Reuters, “If there was 200 million Google Glasses sold, it would be a different perspective. There’s no market at this point.”

Although Google continues to say it’s 100% committed to Glass and the development of the product, the market may not be.

For more, check out the Reuters article in the source link.

Source: Reuters

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CF-Auto Root updated for Android Lollipop on Nexus devices

Posted by wicked November - 15 - 2014 - Saturday Comments Off


Want a quick way to root your Nexus device?

In the past, one such option has been CF-Auto Root — until now, that option hasn’t been available for Lollipop users.

But with a recent update by XDA Senior Recognized Developer Chainfire, Nexus devices running Android 5.0 can join in on the fun. Hit the break for details:

The included devices are as follows:

  • Nexus 4
  • Nexus 5
  • Nexus 7 (2012)
  • Nexus 7 (2013)
  • Nexus 9
  • Nexus 10

Here’s an official changelog of sorts:

  • The new variants of CFAR have the SuperSU ZIP embedded
  • A second included ZIP (if on Lollipop or newer) patches the current kernel to run SuperSU at boot
  • Current CFARs have SuperSU v2.20 which is not currently available elsewhere and only has CFAR compatibility

For more, hit the source link.

Source: XDA Developers




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LG G3 (D855) gets Lollipop through flashable ROM from latest build

Posted by wicked November - 11 - 2014 - Tuesday Comments Off


So far, LG has only pushed the Lollipop update to the G3 in Poland, but that won’t stop others from enjoying it. If you have the European model (D855), Skin1980 from XDA has a surprise for you.

He put together a flashable Zip that’s even rootable. You will need the TWRP recovery installed and you will need to do a factory reset. If this is something that interests you, hit the source link below for full instructions, and be sure to consider giving Skin1980 a donation because I’m sure this took a lot of work.

source: XDA

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Legendary developer Chainfire roots Nexus 9 mere hours after the source code is made public

Posted by wicked November - 5 - 2014 - Wednesday Comments Off


It was only a matter of time before the Nexus 9 was rooted, and thanks to veteran developer Chainfire, that time is now. Less than a few hours after the source code for the HTC-designed tablet was released, Chainfire has come up with a root method that will be familiar to anyone who has used ADB and FastBoot in the past. If you’re looking to get down and dirty with your new tablet, hit the source for instructions on how to get started.

Source: XDA

Come comment on this article: Legendary developer Chainfire roots Nexus 9 mere hours after the source code is made public

Google bringing SD card support back to Android in 5.0 Lollipop

Posted by wicked November - 5 - 2014 - Wednesday Comments Off


It was long thought that Google wanted to phase out external storage in Android, opting for cloud-based solutions, not including SD card slots in Nexus devices and slowly removing SD card functionality in AOSP Android. However, Google is adding some new APIs to Android 5.0 to allow easy access to SD cards after bringing back limited SD functionality in Android 4.4. The new APIs will grant developers access to SD card directories and files after the user grants the application permission once.

Many manufacturers include SD support in their devices by default, but its nice to see Google listening to users and adding native support. Cloud storage is great but traditional expandable storage is nowhere near obsoletion and Google has made a wise move by supporting SD cards in their upcoming version of Android. Do you still use an SD card? Let us know in the comments below!

Source: Android Developers
Via: Phone Arena

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Developers only need a few lines of code to add their apps to Google Voice Search

Posted by wicked October - 30 - 2014 - Thursday Comments Off


We saw glimpses of this at Google I/O, and developers can now make their apps searchable through Google Voice Search. It only takes a few lines of code. Once added, apps can receive the SEARCH_ACTION intent containing the SearchManager.QUERYextra with the search expression.

Examples of such searches might be Ok Google, search pizza on Eat24” or Ok Google, search for hotels in Maui on TripAdvisor.” Imagine the possibilities.

Also, users now have the ability to enable OK Google hot-word detection from any screen, which gives them access to apps even quicker.

Android devices must be on the English local, running Jelly Bean or higher, and have the Google app version 3.5 or higher.

And now for the code…..

<activity android:name=”.SearchableActivity”>
<action android:name=””/>
<category android:name=”android.intent.category.DEFAULT”/>

source: Android Developers

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YouTube WatchMe for Android project brings YouTube live streaming to Android apps

Posted by wicked October - 29 - 2014 - Wednesday Comments Off


YouTube announced the WatchMe for Android project that allows developers to integrate YouTube live streaming into their Android apps. It’s already being utilized by HTC with the Re and Sony with the Live on YouTube app.

It’s an open-source project that uses the YouTube Data API v3, YouTube Live Streaming API, Google Play Services, and Plus API. It’s available on Github and can be customized. It’s still experimental, but you can make sure to keep up with the progress if you subscribe to the YouTube for Developers channel.

How to start using the app
  1. Sync the Github repo
    1. Enable the Youtube Data API v3 and Google+ API.
    2. Create a client ID for Android, using your SHA1 and package name.
  2. Include cross-platform compiled streaming libraries.
  • under src/main/jniLibs/armeabi,
  • another streaming library with modifying VideoStreamingInterface

source: YouTube API Blog


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Google releases Google Fit SDK for developers

Posted by wicked October - 28 - 2014 - Tuesday Comments Off


As we reported earlier today, the long-awaited Google Fit app is now available in the Play Store, and as with most Google Services, the SDK is now available to download for developers. Any developer interested can grab the APIs at the source link and start building apps that take full advantage of the exciting new platform. The SDK allows for full access to all information stored inside Google Fit, opening the door for a plethora of fitness based apps.

Google has already partnered up with multiple companies to bring you applications and services that take full advantage of Google’s new service including: Nike+ Running, Withings HealthMate, Runkeeper, Runtastic, Noom Coach, Strava, MapMyRun, LynxFit, LifeSum, FatSecret, and Azumio. Quite a list, and with the new APIs available to developers, the amount of available Google Fit-powered apps will only grow. For those who’ve tried it, let us know what you think of Google’s new service in the comments below.

Source: Google Developers

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