Did you know: the mobile mile is where 70-90 percent of all app latency and lag occurs

Of all issues that plague most modern smartphones, lag ranks high among the most dreadful. It's present even on steroid-powered handsets like the Samsung Galaxy S6, prompting many a disgruntled user and tech journalist to voice their discontent in comments and blog posts. While interface lag is something that can be blamed on poor effort on the manufacturer side, slow app response times are a different beast that may have a lot less to do with hardware than you think. Most of the times, the actual culprit is what app developers refer to as the "mobile last mile". We'll explain.

As applications grow, they get bigger in all sorts of ways. They get more features, look more polished, and attract a bigger audience. But at the same time, their physical footprint and complexity grows, too. Not that long ago, the average iOS application was 23MB. Nowadays, they stretch to 50MB and beyond, and that's not a case of lazy development. To get a chance at competing in the dense, challenging app space, developers must use everything at their disposal, including third-party libraries and APIs for pulling data, content, ad networks, analytics, and all sorts of necesarry additions. The typical app integrates at least five such, and there are ones that use over 40! The app makes calls to them every time it has to execute a particular action, which slows down performance. Each time a call occurs, the additional time it takes to retrieve all this data impacts the app’s performance, resulting in delayed response and stutter.

Some apps feature multiple API calls for something as seemingly simple as loading a single screen, or configure APIs in a “cascading” manner, in which one function in an app can’t happen until another one has ended. This is a recipe for reduced performance and user frustration. And from an app developer's perspective, it can get pretty bad. If an app won't open swiftly and render the desired content in less than five seconds, it's well on its way towards being deleted, but not before it's "awarded" a scathing app store review. Surveys like the one carried out by Dimensional Research have shown that a mobile app needs to initially load onto user devices in 4 seconds or less, and provide consistent response times between 1 and 3 seconds to satisfy the vast majority of users.

At the same time, it's not just the nature of the trade which demands developers pack increasingly more content into their apps. Reducing the amount of calls means stripping down necessary functionality, while the users that complain of lag also demand all the latest features and will happily switch over to a competing app if it offers significantly more than the one they are currently using. And even if developers optimize to the best of their abilities, the data networks aren’t always as quick to respond to all the activity generated by a given app. Simply put, there can be too much delay in serving a distinct web page via a hyperlink from another web page, or app. And with the way it usually goes, the more bandwidth a network operator provides, the richer the media becomes, which makes speed improvements a non-viable solution to the problem.

This, in short, is the “mobile last mile”, where up to 90% of all app latency and lag occurs. Getting past it is a challenge for developers worldwide, and the proposed ways to tackle the problem are complex enough to be left aside for a separate article. So, next time an app gives you the laggies, don't go on throwing your expensive smartphone at the wall, or immediately reaching for the uninstall button. For the time being, you might just have to live with the lag as an inevitable part of dealing with mobile apps.

source: CIO, Network World



1. TyrionLannister unregistered

Basically what the article is trying to say is: system calls take majority of response time. Surprise, surprise! we all thought the manufacturers and app devs magically created delay.

3. downphoenix

Posts: 3165; Member since: Jun 19, 2010

I still contend it is because of lazy devs, and I bet this article was sponsered and written by lazy devs! /sarcasm

6. joey_sfb

Posts: 6794; Member since: Mar 29, 2012

Why don't you develop some app and show us how its done? The issue is feature vs user expectation vs app lag. See the problem.

2. iushnt

Posts: 3122; Member since: Feb 06, 2013

This might be the reason why my mom's 6 plus got slow overtime..

5. cheetah2k

Posts: 2271; Member since: Jan 16, 2011

I'm not sure that apple devices support "garbage" collection on solid state drives. I know Android 5.0 and beyond do support it.. So some lag "over time" is due to the read/write back to onboard storage getting bogged down....

4. chenski

Posts: 774; Member since: Mar 22, 2015

Therefore people who say their phone never lags are all lying

7. BradyCrack

Posts: 835; Member since: Dec 29, 2015

Well phones lag.

8. Inotamira

Posts: 173; Member since: Feb 06, 2016

It's called "stop with the insane amount of ads" because basically this is how the article reads to me. "API's that pull in the ads slow things down" which translates to me as "devs want money, deal with the ads" which makes perfect sense but isn't an excuse, I'm happy to pay for an app if I'm at least allowed to try it and see if it's worth it, which I can thanks to google play's return policy, and those games lack ads, usually, and tend to be lag free.

9. fancollo

Posts: 130; Member since: Dec 30, 2015

i just thought i'd have bigger problems in my life and now "smartphone-lag" caught me as a suprise, what shall i do..we need a task force to solve the problem immediately, we can't live with lag on a phone guys. An apple + google summit is needed. We need to spread the word and make this fix happen. how am i supposed to tell my mum, that it took me 1.3 seconds to open the train time table app... and therefore wasted my entire 1.3 seconds of live waiting for a decent train time table with delay of up to 10 min...

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