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Category: iOS

Looking for performance clues

We’ve written before about how the operating system and other software can influence test scores and even battery life. Benchmarks like the XPRTs provide overall results, but teasing out which factors affect those results may require some detective work. The key is to collect individual data points as evidence to what may be causing performance changes.

The Apple iOS 11 rollout last month is an excellent example of the effect of software on device performance. Angry tweets started almost immediately after the update, claiming that iOS 11 drained device batteries. iPhone users here at PT experienced similar issues. What was the cause of that performance drop? The hardware remained the same. So, did software cause the problem?

Less than a week after the rollout, Mashable published an explanation of possible causes. The article quotes research from mobile security firm Wandera showing that, for the 50,000 “moderate to heavy iPhone and iPad users” in the study, devices running iOS 11 burned through their battery at much faster rates than the same devices running iOS 10. They cite two possible causes:

    • devices often re-categorize the files stored on them for every new OS install, which may account for some of the battery issues.
    • many apps are not optimized for iOS 11 yet.

 

While these explanations make sense, with a little more digging, we could get closer to actually solving the mystery instead of guessing at the causes. After all, it is also possible that people are using iOS 11 differently from iOS 10. So, how could a dedicated sleuth investigate further? Anyone using benchmarks and hands-on testing to sift through various scenarios and configurations could get us closer to solving this mystery and any other software-based performance anomalies. But it’s a daunting task—changing only one variable at a time and recording the results is like pounding the streets and knocking on doors to solve a case.

In all likelihood, some combination of Apple iOS updates and application changes will improve the battery life for iOS 11. In the meantime, we wish we had an XPRT that could test battery life on iOS. Who knows, maybe some future version of WebXPRT will be able to help in future sleuthing.

Eric

Digging deeper

From time to time, we like to revisit the fundamentals of the XPRT approach to benchmark development. Today, we’re discussing the need for testers and benchmark developers to consider the multiple factors that influence benchmark results. For every device we test, all of its hardware and software components have the potential to affect performance, and changing the configuration of those components can significantly change results.

For example, we frequently see significant performance differences between different browsers on the same system. In our recent recap of the XPRT Weekly Tech Spotlight’s first year, we highlighted an example of how testing the same device with the same benchmark can produce different results, depending on the software stack under test. In that instance, the Alienware Steam Machine entry included a WebXPRT 2015 score for each of the two browsers that consumers were likely to use. The first score (356) represented the SteamOS browser app in the SteamOS environment, and the second (441) represented the Iceweasel browser (a Firefox variant) in the Linux-based desktop environment. Including only the first score would have given readers an incomplete picture of the Steam Machine’s web-browsing capabilities, so we thought it was important to include both.

We also see performance differences between different versions of the same browser, a fact especially relevant to those who use frequently updated browsers, such as Chrome. Even benchmarks that measure the same general area of performance, for example, web browsing, are usually testing very different things.

OS updates can also have an impact on performance. Consumers might base a purchase on performance or battery life scores and end up with a device that behaves much differently when updated to a new version of Android or iOS, for example.

Other important factors in the software stack include pre-installed software, commonly referred to as bloatware, and the proliferation of apps that sap performance and battery life.

This is a much larger topic than we can cover in the blog. Let the examples we’ve mentioned remind you to think critically about, and dig deeper into, benchmark results. If we see published XPRT scores that differ significantly from our own results, our first question is always “What’s different between the two devices?” Most of the time, the answer becomes clear as we compare hardware and software from top to bottom.

Justin

Exploring virtual reality

We’ve talked a lot in recent weeks about new technologies we are evaluating for the XPRTs. You may remember that back in June, we also wrote about sponsoring a second senior project with North Carolina State University. Last week, the project ended with the traditional Posters and Pies event. The team gave a very well thought‑out presentation.

NCSU VR blog pic 1

As you can tell from the photo below, the team designed and implemented a nifty virtual reality app. It’s a room escape puzzle, and it looks great!

NCSU VR blog pic 2

The app is a playable game with the ability to record the gameplay for doing repeatable tests. It also includes a recording that allows you to test a device without playing the game. Finally, the app lets you launch directly into the prerecorded game without using a viewer, which will be handy for testing multiple devices.

The team built the app using the Google Cardboard API and the Unity game engine, which allowed them to create Android and iOS versions. We’re looking forward to seeing what that may tell us!

After Posters and Pies, the team came to PT to present their work and answer questions. We were all very impressed with their knowledge and with how well thought out the application was.

NCSU VR blog pic 3

Many thanks to team members Christian McCurdy, Gregory Manning, Grayson Jones, and Shon Ferguson (not shown).

NCSU VR blog pic 4

Thanks also to Dr. Lina Battestilli, the team’s technical advisor, and Margaret Heil, Director of the Senior Design Center.

We are currently evaluating the app, and expect to make it available to the community in early 2017!

Eric

 

Tracking device evolution with WebXPRT ’15, part 2

Last week, we used the Apple iPhone as a test case to show how hardware advances are often reflected in benchmark scores over time. When we compared WebXPRT 2015 scores for various iPhone models, we saw a clear trend of progressively higher scores as we moved from phones with an A7 chip to phones with A8, A9, and A10 Fusion chips. Performance increases over time are not surprising, but WebXPRT ’15 scores also showed us that upgrading from an iPhone 6 to an iPhone 6s is likely to have a much greater impact on web-browsing performance than upgrading from an iPhone 6s to an iPhone 7.

This week, we’re revisiting our iPhone test case to see how software updates can boost device performance without any changes in hardware. The original WebXPRT ’15 tests for the iPhone 5s ran on iOS 8.3, and the original tests for the iPhone 6s, 6s Plus, and SE ran on variants of iOS 9. We updated each phone to iOS 10.0.2 and ran several iterations of WebXPRT ’15.

Upgrading from iOS 8.3 to iOS 10 on the iPhone 5s caused a 17% increase in web-browsing performance, as measured by WebXPRT. Upgrading from iOS 9 to iOS 10 on the iPhone 6s, 6s Plus, and SE produced web-browsing performance gains of 2.6%, 3.6%, and 3.1%, respectively.

The chart below shows the WebXPRT ’15 scores for a range of iPhones, with each iPhone’s iOS version upgrade noted in parentheses. The dark blue columns on the left represent the original scores, and the light blue columns on the right represent the upgrade scores.

Oct 27 iPhone chart

As with our hardware comparison last week, these scores are the median of a range of scores for each device in our database. These scores come both from our own testing and from device reviews from popular tech media outlets.

These results reinforce a message that we repeat often, that many factors other than hardware influence performance. Designing benchmarks that deliver relevant and reliable scores requires taking all factors into account.

What insights have you gained recently from WebXPRT ’15 testing? Let us know!

Justin

Getting it right

Back in April Bill announced that we are working on a cross-platform benchmark. We asked for your thoughts and comments, and you’ve been great! We really appreciate all the great ideas.

We’ve been using code from MobileXPRT and TouchXPRT as the basis for some experiments. In his post, Bill talked about the difficulty of porting applications. However, even though we have expertise in porting applications, it’s proving more difficult than we originally thought. Benchmarks are held to a higher standard than most applications. It’s not enough for the code to run reliably and efficiently, it must compare the different platforms fairly.

One thing we know for sure: getting it right is going to take a while. However, we owe it to you to make sure that the benchmark is reliable and fair on all platforms it supports. We will, of course, keep you informed as things progress.

In the meantime, keep sending your ideas!
Eric

Looking ahead

It’s only been a couple of weeks since we announced a cross-platform XPRT. It’s still early days, but we’ve already started getting ideas from vendors and media—from both people within the community and those who have not yet joined. We’re incorporating these ideas into our investigations, and plan to be sending a design document for the community to critique in a few weeks.

However, we are always looking ahead and Bill’s trip to IDF16 got us thinking about future benchmarks. Virtual reality is obviously going to be big. Bill said that he thinks he saw more things using the Oculus Rift than there are Oculus Rifts in the world! The Internet of Things has been ramping up for a while now, and shows no sign of slowing down. Computer vision is another emerging area, one with many possible applications. There are a lot of exciting possibilities!

As always, we want to know what you think. What upcoming technologies are you excited about? What would like to see in these benchmarks? Please let us know!

Eric

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