Profiler window
Attaching to Unity players
To profile your game running on an other device or a player running on another computer, it is possible to connect the editor to that other player. The dropdown Active Profiler will show all players running on the local network. These players are identified by player type and the host name running the player “iPhonePlayer (Toms iPhone)”. To be able to connect to a player, the player must be launched with the Development Build checkbox found in the Build Settings dialog. From here it is also possible to tick a checkbox to make the Editor and Player Autoconnect at startup.
Profiler Controls
Profiler controls are in the toolbar at the top of the window. Use these to turn profiling on and off, navigate through profiled frames and so on. The transport controls are at the far right end of the toolbar. Note that when the game is running and the profiler is collecting data clicking on any of these transport controls will pause the game. The controls go to the first recorded frame, step one frame back, step one frame forward and go to the last frame respectively. The profiler does not keep all recorded frames, so the notion of the first frame should really be though of as the oldest frame that is still kept in memory. The “current” transport button causes the profile statistics window to display data collected in real-time. The Active Profiler popup menu allows you to select whether profiling should be done in the editor or a separate player (for example, a game running on an attached iOS device).
Deep Profiling
When you turn on Deep Profile, all your script code is profiled - that is, all function calls are recorded. This is useful to know where exactly time is spent in your game code.
Note that Deep Profiling incurs a very large overhead and uses a lot of memory, and as a result your game will run significantly slower while profiling. If you are using complex script code, Deep Profiling might not be possible at all. Deep profiling should work fast enough for small games with simple scripting. If you find that Deep Profiling for your entire game causes the frame rate to drop so much that the game barely runs, you should consider not using this approach, and instead use the approach described below. You may find deep profiling more helpful as you are designing your game and deciding how to best implement key features. Note that for large games deep profiling may cause Unity to run out of memory and so for this reason deep profiling may not be possible.
Manually profiling blocks of your script code will have a smaller overhead than using Deep Profiling. Use Profiler.BeginSample and Profiler.EndSample scripting functions to enable and disable profiling around sections of code.
View SyncTime
When running at a fixed framerate or running in sync with the vertical blank, Unity records the waiting time in “Wait For Target FPS”. By default this amount of time is not shown in the profiler. To view how much time is spent waiting, you can toggle “View SyncTime”. This is also a measure of how much headroom you have before losing frames.
Profiler Timeline
The upper part of the Profiler window displays performance data over time. When you run a game, data is recorded each frame, and the history of the last several hundred frames is displayed. Clicking on a particular frame will display its details in the lower part of the window. Different details are displayed depending on which timeline area is currently selected.
The vertical scale of the timeline is managed automatically and will attempt to fill the vertical space of the window. Note that to get more detail in say the CPU Usage area you can remove the Memory and Rendering areas. Also, the splitter between the timeline and the statistics area can be selected and dragged downward to increase the screen area used for the timeline chart.
The timeline consists of several areas: CPU Usage, Rendering and Memory. These areas can be removed by clicking the close button in the panel, and re-added again using the Add Area drop down in the Profile Controls bar.
Note that the coloured squares in the label area can control whether the associated timeline is displayed or not. To remove a sample from the display click on the colour key. The key will dim and the data will be removed from the graph. This can be useful to identify the cause of spikes in the CPU graph, for example.