Tuning for Speed - iOS Core Animation - page 258

As mentioned earlier, you should only ever profile the Release configuration of your app.
Fortunately, the profiling option is set up to use the Release configuration by default, so
you don't need to adjust your build scheme when you are profiling.
The tools we are primarily interested in are as follows:
▪ Time Profiler —Used to measure CPU usage, broken down by method/function.
▪ Core Animation —Used to debug all kinds of Core Animation performance issues.
▪ OpenGL ES Driver —Used to debug GPU performance issues. This tool is more
useful if you are writing your own OpenGL code, but occasionally still handy for
Core Animation work.
A nice feature of Instruments is that it lets us create our own groupings of tools. Regardless
of which tool you select initially, if you open the Library window in Instruments, you can
drag additional tools into the left sidebar. We'll create a group of the three tools that we are
interested in so that we can use them all in parallel (see Figure 12.2).
Figure 12.2 Adding additional tools to the Instruments sidebar
Time Profiler
The Time Profiler tool is used to monitor CPU usage. It gives us a breakdown of which
methods in our application are consuming most CPU time. Using up a lot of CPU isn't
necessarily a problem—you would expect your animation routines to be very CPU
intensive because animation tends to be one of the most demanding tasks on an iOS device.