64-Bit Support

ART was designed in mind with modularity of the various target architectures in which it is supposed to run on. As such, it provides a multitude of compiler-backends targeting today’s most common architectures such as ARM, x86 and MIPS. In addition, 64-bit support for ARM64, x86-64 and while still not implemented, also MIPS64.

While we have gone more in depth of the advantages and implications of switching over to 64-bit architectures in the iPhone 5s review, the main points to take away are the availability of an increased address space, generally increased performance, and vastly increased cryptographic capabilities and performance, all while maintaining full 32-bit compatibility with all existing apps.

An important difference that Google is applying over Apple, at least inside VM runtime applications, is that they are using reference compression to avoid the usual memory bloat that comes with the switch to 64-bit. The VM retains simple 32-bit references.

Google has made available some preview benchmarks showcasing the performance gains both on x86 and ARM platforms. The x86 benchmarks were executed on a Intel BayTrail system, and show a 2x to 4.5x speedup in various RenderScript benchmarks. On the ARM side, the crypto performance gains over 32-bit were showcased on an A57/A53 system. Both of these are relatively non-representative of one should really expect in real-world use-cases so they’re not that useful as a performance prediction.

However Google also made some interesting numbers available on one of their internal build-systems called Panorama. Here we can see a 13 to 19% increase in performance by simply switching over the ABI. It is also good to see how ARM’s Cortex A53 is able to make a bigger impact on performance when in AArch64 mode than the A57 cores.

Google claims that 85% of all current Play Store apps are immediately ready to switch over to 64 bit - which would mean that only 15% of applications have some kind of native code that needs targeted recompiling by the developer to make use of 64-bit architectures. This is a great win for Google and I expect the shift over to 64-bit to be very fast once silicon vendors start shipping 64-bit SoCs in the coming year.


In many points, Google has delivered its “Performance boosting thing” and addressed much of the shortcomings that have plagued Android for years.

ART patches up many of the Achilles’ heels that comes with running non-native applications and having an automatic memory management system. As a developer, I couldn’t have asked for more, and most performance issues that I needed to work around with clever programming no longer pose such a drastic problem anymore.

This also means that Android is finally able to compete with iOS in terms of application fluidity and performance, a big win for the consumer.

Google still promises to evolve ART in the future and its current state is definitely not what it was 6 months ago, and definitely not what it will be once the L release is made available in its final form in devices. The future looks bright and I can’t wait to see what Google will do with its new runtime.

Garbage Collection: Theory and Practice
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  • hechacker1 - Tuesday, July 1, 2014 - link

    I experienced the same thing with my droid bionic. After flashing it, I think I had to wait 30 minutes before I could even login due to ART compiling apps. I just left my phone on and plugged in and walked away.

    But the experience after was much better after that long wait. I assume that production firmware would already have that step included in the restore.
  • highlnder69 - Thursday, July 3, 2014 - link

    Where did you get the new firmware for the Droid Bionic that includes ART?
  • bengildenstein - Wednesday, July 2, 2014 - link

    I have the 2012 Nexus 7, and while the performance is far from perfect (it is notably slow when app loading and horrendous when anything is accessing the SSD), the latest Chrome Beta has brought nearly flawless performance and (seeming) 60fps scrolling with little, if no jank for all but very heavy sites. In fact, there are a number of apps that I use regularly that scroll flawlessly on this ageing system.

    There are still apps that run slower than they should, and typically apps load slower than I would like, and many exhibit jank when scrolling (in fact anything with a list of pictures), and I'm hoping that Android L improves these situations (if the 2012 Nexus 7 is updated at all). But of late, I'm pretty happy with the optimizations made. Ever since the recent 4.4.4 update, it seems that the OS is running apps much more smoothly than ever before.

    If L improves the performance as you describe, then Android will attain that fluidity and swiftness that iOS and WP have been known for across most apps, which will be very welcome.
  • Samus - Wednesday, July 2, 2014 - link

    If Google can deliver a product as polished as iOS, Apple has a lot more to be worried about that simply making phones with bigger screens.
  • buckschris - Wednesday, July 2, 2014 - link

    I agree to an extent. Google is making great strides, and the L release appears to bring some very useful user experience "fixes." The only issue at this time is the color schemes we have seen recently in Google app updates and in the demoed Material Design Gmail app. The colors remind me of the colors from the basic 12-pack of Crayola crayons. They don't quite fit the slick new interface.

    What has me most excited is four initiatives by Google to take back control over Android. First, is the lack of customization for 3rd parties using Android Wear, Android Auto and Android TV. Second, is the introduction of stock Android phones under the One program. If the initiative takes off, that would be a lot of phones running Google controlled and delivered stock Android. Third, is the as-of-yet unofficial Android Silver program - bringing Google Play Editions to carriers, with the software side apparently also to be controlled and delivered by Google. Putting "Silver" devices running stock Android in direct competition with the manufacturer's skinned phones should and hopefully will force the Samsung's of the world to up their game. Fourth, is an iOS system for introducing new versions of Android. This sneak peak will, hopefully, allow the manufacturers to do their appropriate skinning and get updates out in a much more timely manner.

    All told, exciting times for those who appreciate technology and the advances we've seen over the last 15-20 years. I'm not sure what that next BIG product category is. I'm not sold that it's smart watches. What is the elevator speech for a smart watch? It's not an intuitive buy or justification for a lot of folks.
  • tacitust - Thursday, July 3, 2014 - link

    For watches, once they are hard to distinguish from classic analog watches (thin design, top-quality screen tech, decent battery life) then the pitch is "high-tech fashion accessory" which you will be able to buy from Rolex and other expensive watch manufacturers.

    But if you're talking about wearables as a class (i.e. not necessarily watches) then I think it has to be personal health monitoring. At first, it'll be just basic stuff like heart rate, blood pressure, exercise monitoring, but eventually (years from now) as the medtech improves, it may be able to do things like warn you of an impending heart attack or stroke, or perhaps a vitamin deficiency, etc.
  • name99 - Wednesday, July 2, 2014 - link

    If Google is willing to ship an update that effectively freezes the system on first launch for 30 minutes while providing no UI to explain what is going on, I don't think Apple has much to be worried about...

    (Apple is not perfect on this score; in particular there are time when OSX shuts down when one has an uncomfortably long period of watching a spinner while the system is doing god knows what. But they at least understand the principle of user feedback, ESPECIALLY during first boot.)
  • Devo2007 - Wednesday, July 2, 2014 - link

    Right now, L is a Developer Preview. Not even really a beta. I'm sure Google understands user feedback is useful, but this is not something really designed for end users.

    Given discussions about this and other issues in various places though, it seems many people don't understand this concept and are expecting far too much out of the preview.
  • darwinosx - Thursday, July 3, 2014 - link

    Everything Google does is a beta.
  • Alexey291 - Tuesday, July 8, 2014 - link

    so even alpha is a beta? kay

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