Gustavo Pinto and Fernando Castor (via Jeremy W. Sherman):
One of the main challenges of software energy consumption research is to bring analysis to the static level. Currently, software energy consumption instrumentation can only be conducted at runtime. This approach has several limitations; such as sophisticated (and expensive) hardware equipment or applicability only to specific hardware configurations. This fact has the potential of limiting the usability of software energy consumption tools.
[…]
Pinto et al. observed that just updating from Hashtable to Concurrent HashMap in a Java program can yield a 3.5x energy savings. In particular, this transformation yields a 1.4x and a 9.2x energy savings in CPU and DRAM, respectively. As another example, Pathak et al. observed that I/O operations consume more energy partly because of the tail energy phenomenon. According to the authors, bundling I/O operations together can mitigate this tail energy leak. These results have a clear implication: Tools to aid developers in quickly refactoring programs can be useful if energy is important.
[…]
Li et al. discussed how to improve energy efficiency by favoring darker colors instead of lighter ones for smartphones with OLED displays. Using a search-based multi-objective approach, Linares-Vasquez et al. automatically optimized energy consumption and contrast, while using consistent colors with respect to the original color palette. Oliveira Jr. et al. analyzed the energy consumption of Android app development approaches, Java, JavaScript, and Java + C++, in both benchmarks and real apps. In both scenarios it was observed that different approaches have different impacts on energy. In particular, combining different approaches can yield more than an order of magnitude energy savings in compute-intensive apps.
[…]
Pathak et al. focus on understanding and monitoring system calls that are related to I/O operations. As a results, they found that most of the energy consumed in free apps is related to third-party advertisement modules (which can be responsible for up to 75% of the overall energy consumed by an app).
Advertising Android Battery Life iOS Java Programming Refactoring
Brent Simmons:
WebView — good ’ol trusty friend — has a bunch of things that WKWebView is missing.
The new web view has no built-in support for finding text, for instance. I’m not sure what I’m going to do about this, since the ability to hit cmd-F and look for some text is a pretty fundamental thing, and I can’t skip it.
It also has no delegate method for when you mouse over a link. Seems like another fundamental thing, right? Any browser offers you a status bar or some way to see the URL of the link your mouse is over.
Given the level of progress over the last 3.5 or so years, it seems like WKWebView is the future, and too bad for you if you need more features. Maybe you can hack some of them together using JavaScript. With Apple no longer dogfooding WebView, how much longer will it be supported? This is the sort of thing that worries me about iOS APIs coming to the Mac.
Update (2018-05-14): Howard Oakley:
That may be true, but when I had implemented that in LockRattler, which runs on El Capitan and later, Xcode decided that I couldn’t use WKWebView because of implementation bugs. It only works in Sierra and later, not in El Capitan.
Mac macOS 10.13 High Sierra Programming WebKit WKWebView
Sarah Perez (MacRumors):
The company’s revised wording now states:
4.2.6 Apps created from a commercialized template or app generation service will be rejected unless they are submitted directly by the provider of the app’s content. These services should not submit apps on behalf of their clients and should offer tools that let their clients create customized, innovative apps that provide unique customer experiences.
Another acceptable option for template providers is to create a single binary to host all client content in an aggregated or “picker” model, for example as a restaurant finder app with separate customized entries or pages for each client restaurant, or as an event app with separate entries for each client event.
This is Apple’s attempt to clarify how it thinks about templated apps.
Core to this is the idea that, while it’s fine for small businesses and organizations to go through a middleman like the app templating services, the app template providers shouldn’t be the ones ultimately publishing these apps on their clients’ behalf.
Instead, Apple wants every app on the App Store to be published by the business or organization behind the app. (This is something that’s been suggested before). That means your local pizza shop, your church, your gym, etc. needs to have reviewed the App Store documentation and licensing agreement themselves, and more actively participate in the app publishing process.
This makes sense to me.
Brian Stucki:
Happy to see this update. 1) I like it when I load a random app and it’s a design I’m already familiar with and 2) makes apps affordable for small business and 3) the services that build and sign these apps are a popular customer for @MacStadium Mac clouds. Win-win-win.
Previously: Apple Widens Ban on Templated Apps.
Update (2017-12-22): See also: John Voorhees.
Update (2018-02-22): Matt Long:
Apple drops another bomb WRT white label apps. Grandfathered apps must be transferred to customer app store account if updated after April 1.
App Store iOS iOS 11
Matthew Panzarino (Hacker News):
Here’s a statement that Apple provided when I inquired about the power profile that people were seeing when testing iPhones with older batteries:
Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices. Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components.
Last year we released a feature for iPhone 6, iPhone 6s and iPhone SE to smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions. We’ve now extended that feature to iPhone 7 with iOS 11.2, and plan to add support for other products in the future.
John Gruber:
Prior to adding this feature to iOS last year, iPhones with older declining batteries were shutting down unexpectedly when taxed at peak performance. That’s obviously not good. So now, iPhones with older declining batteries are throttled, when necessary, to keep them running. But now Apple faces accusations that they’re deliberately slowing these devices down to convince people to buy new iPhones.
Jason Koebler:
iFixit teardown engineer Jeff Suovanen performed similar tests with iFixit employees’ phones and shared the data with Motherboard.
Suovanen found that iPhone 6S devices that still had their original batteries (they are about two years old now) had benchmark scores that were up to 57 percent lower than the GeekBench average. Replacing the battery instantly improved the benchmark scores drastically; he saw 70 percent swings in benchmark performance after swapping the old battery for a new one.
“Everyone came back a day later and said, ‘Wow, it works so much faster,’” Suovanen told me on a phone call.
[…]
What makes it worse is that Apple does not make it easy to replace the battery yourself, discourages third party repair, and doesn’t have the first party repair infrastructure to handle large numbers of in-store battery swaps, especially in states that don’t have lots of Apple Stores.
Andrei Frumusanu:
Capacity and supply voltage of a battery decreases over time as a function of charge cycles and charging behaviour (Higher charging currents causing more degradation per cycle). This causes the total useable battery capacity before the cut-off voltage to decrease.
The problem facing the iPhones as Apple explains it is however two-fold; the issue at hand happens only during load spikes in which the battery isn’t able to maintain a high enough voltage for the PMIC to reliably be able to use as a source.
SoC blocks such as CPUs and GPUs can have very short transitions from idle to load causing steep transients and load spikes going above the +10W ranges. As batteries degrade over time and the cell impedance also rises also in function of the state of charge and temperature, the current flow becomes restricted and the cell is no longer able to satisfy the power requirement at a high enough operating voltage.
[…]
If this is the case then another question rises is if this is indeed just a transient load issue why the power delivery system was not designed sufficiently robust enough to cope with such loads at more advanced levels of battery wear? While cold temperature and advanced battery wear are understandable conditions under which a device might not be able to sustain its normal operating conditions, the state of charge of a battery under otherwise normal conditions should be taken into account during the design of a device (Battery, SoC, PMIC, decoupling capacitors) and its operating tolerances.
If the assumptions above hold true then logically the issue would also be more prevalent in the smaller iPhone as opposed to the iPhone Plus models as the latter’s larger battery capacity would allow for greater discharge rates at a given stable voltage. This explanation might also be one of many factors as to why flagship Android and other devices don’t seem to exhibit this issue, as they come with much larger battery cells.
Jacob Kastrenakes (Hacker News):
There is some good reason for Apple to do this. By their nature, lithium-ion batteries degrade over time, storing less and less of a charge. This happens very quickly on a device we use 24/7. So it's not a bad idea for Apple to limit speeds on older phones, such that they don't push things too far on a depleted battery. That absolutely makes the phone more useable — it apparently helps stop random shutdowns, which are a major pain. And I would think it helps with battery life in general as well.
But it also speaks to a really enormous problem with the iPhone: this $700 to $1,000-plus product, as designed, isn't able to function near its peak after just a year of use. That should be unacceptable.
Slowing down the phone is one way to work against aging issues, but there are other, more obvious things Apple could do here. It could put larger batteries in the iPhone in the first place, so that they last longer before this kind of adjustment needs to kick in.
Some of my thoughts:
Apple’s communication has been really poor here. What was the point of hiding this from customers? Instead, Apple let them think they were going crazy and didn’t step in to correct the record when pundits and more technical users kept telling them that, no, Apple doesn’t slow down old phones. This hurts trust and will make more people think Apple does fishy things.
The fix last year for the unexpected shutdown issue was first presented as affecting “a very small number” of phones—all from a particular model—that had defective batteries. Then in February, iOS 10.2.1 included a software fix that used “advanced battery management” to prevent unexpected shutdowns. But Apple again described the problem as affecting only “small number of users,” and it didn’t clearly explain that it was throttling the CPU.
Now, that 10.2.1 fix is being used to spin the current story as old news. What people are talking about now is definitely not what most people thought was happening with 10.2.1. Perhaps part of the confusion is that it seems Apple’s 10.2.1 press briefings included details that did not make it into the published articles or Apple’s official statements. But even Apple geniuses don’t seem to have known what was going on.
The official statement this week seems to deliberately avoid clear language: “smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down.” That does nothing to help the average user understand what is going on or to determine whether they are affected and what they should do.
Does this really only happen when the phone is in imminent danger of shutting down? If so, that would explain why Apple didn’t provide a way for users to opt in. What use is it to opt into making your phone crash? But I’m not sure this matches up with what customers are reporting, including across the board performance problems that suddenly improve when replacing the battery and lower performance even while charging. Nor does it explain all the customers whose phones were not shutting down but who noticed much slower performance following the iOS updates that introduced the throttling.
Spontaneous shutdowns have occurred at least as far back as the iPhone 5s, but they seem more prevalent with newer iPhone designs. Some Android phones are also affected, but to a lesser extent. My guess is that this is because Android phones typically include larger batteries.
This all points to an iPhone design flaw. If phones with larger batteries (and iPads and MacBooks) are not affected, it seems like the problem is that Apple got too aggressive about shaving battery capacity to make its phones thinner. The alternative would be to believe that Apple knew this would happen, kept designing new phones in the same way, and waited this long to implement the software fix.
I’m puzzled by all the people rushing to defend Apple. It’s not that I think Apple purposely did this so people would buy new phones. But there’s no evidence the other way, either, so this is hardly vindication. Even if the conspiracy theories were true, there wouldn’t be a smoking gun memo where Tim Cook decreed that old phones be slowed down. It would have been presented in a way that offered plausible deniability. The unexpected shutdown issue would be the perfect cover, and the malfeasance would be in the details of how it was tuned, e.g. throttling more phones—or throttling them more aggressively—than necessary to avoid the unexpected shutdowns.
Apple’s actions are in fact consistent with a desire to increase sales. Presumably, they believe that thinner phones sell better. But an iPhone that spontaneously shuts down is not going to get someone to buy a new iPhone—it’ll get them to look at Android. On the other hand, an iPhone that feels slow compared with a fast new iPhone is a pretty good inducement to upgrade, especially when you have no way of knowing that a fresh battery would make your old phone fast again. Many iPhones users do not even know that the battery can be replaced. They think their only choice is to get a whole new phone.
If this were truly a small issue, you would think Apple would have announced the problem more clearly and offered free battery replacements to the affected users. But if it’s actually a more widespread problem, the incentive would be to try to keep it a secret and to avoid the costs of replacing lots of batteries, overloading the stores, and having everyone see from the long lines just how many iPhones were affected. Not telling customers surely prevented many of them from getting warranty replacements that they would have been entitled to. My guess is that Apple’s decisions came from its “we know your needs better than you” philosophy rather than anything this cynical, but it looks bad regardless.
Replacing the battery is inconvenient, potentially very time consuming, and rather costly at $79, when Apple’s costs for the battery itself are far lower. Apple’s policy is only to replace batteries that won’t hold 80% of their original charge. Yet there have been reports both of batteries seemingly in better condition also experiencing problems and of phones experiencing clear symptoms, where Apple refused to replace the battery, even if the customer paid. I think many customers would prefer a slightly thicker phone that made these issues irrelevant.
It’s important to keep in mind that not all iPhone slowness is necessarily due to this throttling. Not letting the customers see whether throttling is happening makes this misattribution more likely and feeds the narrative that Apple is purposely slowing phones.
The broader question is whether Apple was properly looking out for customers’ interests. I would say yes for the throttling but no for making the failure silent, which prevented customers from making informed choices. iOS does eventually tell you that your battery needs to be replaced, but only when it’s in really terrible condition.
Apple is now being sued, but it seems like this lawsuit was written before we knew Apple’s explanation for the behavior.
Lastly, how long should we expect a phone to last? Especially one like the iPhone X? With higher prices, the move away from carrier contracts, and diminishing returns for the camera and other new features, it seems natural that people will want to keep their phones longer. But that seems totally at odds with the design and battery choices Apple is making and the 2-year limit for AppleCare.
Previously: Does iOS Throttle CPUs When Using a Degraded Battery?.
Update (2017-12-22): Rene Ritchie describes additional power management that slows down the CPU separately from the protection during load spikes.
More lawsuits have been filed.
Kirk McElhearn recommends iMazing for checking your battery’s health.
Update (2017-12-23): I already find the iPhone 6–8 thin enough that I need a case to hold them comfortably. I’d much rather carry extra battery than inert plastic.
After the Reddit story broke, an Apple genius told Michael Glenn that iOS does not throttle when the battery is degraded; he was able to fix the performance issues on his iPhone by wiping and restoring it, which got rid of a “rogue system process that somehow persisted through upgrades and restarts” (via John Gruber).
Update (2017-12-28): See also: Accidental Tech Podcast.
Apple has posted a statement.
Update (2018-01-01): Antonio Fonseca:
It seems the SoC team needs to interact more with the battery / engineering team and all of them with the industrial design team. It seems like things are a bit out of sync when it comes to goals for the iPhone project.
Nilay Patel:
Processor speed is just one piece of the battery- and performance-management puzzle, according to Apple: iPhones with older batteries may also more aggressively dim their screens, have lower maximum speaker volumes, and even have their camera flashes disabled when the system needs more peak power than the battery can provide. But other core features, like the cell radio, GPS, and camera quality, aren’t affected, Apple says. The whole approach actually quite clever, but cleverness isn’t a great substitute for speed.
In any event, Apple has a long way to go rebuilding trust with its customers — this story broke well past the tech press and hit TV morning shows and local news with zero nuance about “smoothing instantaneous peaks” and battery chemistry degradation. A lot of people already believed that Apple slowed down their iPhones, and this wave of news was a big data point confirming that for them. It’s going to be a difficult road back.
Ian Spencer:
Key phrase is “whose battery needs to be replaced”. In my experience Apple is loathe to admit a device (iPhone or Mac) has battery problems.
Mitchel Broussard:
In response, iFixit has decided to match that price point and lower the cost of every DIY iPhone battery fix kit to $29 or less.
Rene Ritchie:
No #iPadSlow: Basically, the iPad battery is so big there’s much less concern over power spikes and so Apple hasn’t added them to the same advanced power management system that iPhone 6, iPhone SE, iPhone 6s, and iPhone 7 are on.
dwc1 (via Jon Maddox):
I went to the Genius Bar yesterday and got a walkin appointment for my T-Mobile purchased 6s. The wait time was quoted as 1 hour but took 20 mins. They ran very deep diagnostics to see if I qualify for the $29 offer which I was not expecting since I thought you could just ask for replacement on demand. They told me my battery was working well enough and almost turned me down. I had to press hard that the battery just does not hold the charge long enough anymore. The tech found a workaround by prompting me to sort of claim that the device shuts down unexpectedly on occasion. Once I said yes to shutdown issue that they replaced the battery for FREE. It looks like Apple will be sort of strict about these $29 battery replacements. I also had to leave my phone for the actual repair for about 90 mins wait time while they did the work.
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