The top track aggregates all the data from all individual thread and CPU core tracks. The percentage of CPU cycles from 0% to 100% at each sample point is shown over time on a graph called the “timeline” or “track.” There are multiple tracks. It gathers the same data about iOS SDK functions. In simplest of terms, Time Profiler collects information about your app while it’s running, determines you how long each of your functions takes to run, and also figures out the percentage of CPU cycles each of your functions is using. We’re going to use the Time Profiler to analyze the performance of my sample app’s code. According to Apple, the Time Profiler template “Performs low-overhead time-based sampling of processes running on the system’s CPUs.” The Xcode Instruments’ Time Profiler template is the best template to start with when looking for app performance problems and/or determining how to improve performance. Using Instruments to identify performance problems We turn to the darn good tools that already come bundled free with Xcode. Some apps are so slow that people just delete them.ĭo we find out why our apps are so slow by using just print statements and breakpoints? I hope not, but I’ve seen more than a fair share of Stone Age “optimization” techniques. Users keep demanding more, better, and faster features. Software keeps getting more and more complex. Since the code is readable and logically organized, it can be extended, reused, debugged, and maintained easily.īut by goodness, nobody’s perfect, not even me -). ![]() Time is saved because team members can easily read each other’s semantically clear code. Advanced language features usually let us do more by writing less and very expressive code. Most of the time, these advanced features save software development boutiques enormous amounts of time and resources. Sure, once in a while you’ll have a use case where advanced code features don’t pay off, i.e., code is badly written or not used for the intended purpose. There are costs to these high-level features, but I would argue that in most cases, language compiler optimizations, operating systems enhancements, and faster hardware (like solid state drives and multi-core processors), make up for the costs. Do we realize that there are great tools like Xcode Instruments that help us find awkward implementations of these techniques and give us the opportunity to come up with our own optimizations? Yes. So do we give up all hope or do we accept the fact that compiler designers have come up with brilliant optimizations that ameliorate the use of such high-level technologies? We believe in Swift’s compiler designers. On a subconscious level, the curmudgeons don’t understand these technologies. On a conscious level, the curmudgeons usually reject these technique because of their supposed “massive” performance cost. I still run across curmudgeons who flat out reject techniques like object-oriented programming (especially inheritance and polymorphism), protocols and protocol-oriented programming (especially composition), generics, and closures. ![]() The pic below shows it.My original article - “How to Use Xcode Instrument to Optimize Your Swift Code” - was published on. ![]() Although for this tutorial I have selected a random spike just to demonstrate how its done. Some random spikes are okay can also be looked into but many a times they don’t matter because objects created are also destroyed after that and that spike might have occurred because of some urgent need of memory. ![]() In this way you could figure out that something is wrong with that particular line and needs to be deep dived into to find out the issue and maybe that is the cause of your leak.ĭetecting increasing memory issue To detect increasing memory issue, just select the region where memory is continuously increasing. P.S.:- Did you see above in Pic 4, how the two lines related to FIRNetwork showed up and how in Pic 5, the code just opened up? This would only be seen if you run your code in with dsym on by enabling DWARF with DSYM option in the Debug Information Format of Build options under Build Settings tab for debug mode.Īs you can see in Pic 5, the code for FIRNetworkURLSession opened up, and line 141 is highlighted.
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