The default capture settings work well for most situations but you can change the capture settings to customize your profiling session. These settings include the sample rate, buffer size, and duration of the capture.
If you are recording call stacks, compile your images and libraries with frame pointers enabled using the -fno-omit-frame-pointer compiler option. For Arm®v7 software applications, you must also disable the Thumb® instruction set by using the -marm option.
In the Start view, select the Use advanced mode checkbox.
Click Capture Settings.
The Normal sample frequency is 1kHz for CPU events, and 2kHz for GPU events. To change how regularly Streamline collects samples, change Sample rate to:
High to increase sample frequency to 10kHz in both CPU and GPU events. This enhances visibility, but also increase overhead.
Low if you have a slow target, or if the target is heavily loaded, for a longer capture at a sample frequency of 100Hz for both CPU and GPU events.
None to have the lowest level of intrusion on your code, and disable periodic sampling. Any report columns that rely on sampling show zero values.
Note
For older GPUs, such as Bifrost and earlier, GPU sampling in Normal mode is set to 1kHz.
If you do not want to display real-time data during a capture session, set Buffer mode to the appropriate buffer size. The capture ends when the buffer is full:
| Buffer mode | Buffer size |
|---|---|
| Large | 256MB |
| Medium | 64MB |
| Small | 16MB |
Set Buffer mode to Streaming to enable Live view and allow streaming of target data directly to your host during capture.
To record call stacks and improve the visibility of the behavior of the target, select Call stack unwinding.
Recording call stacks increases the amount of raw data that the target sends to the host.
To support call stack unwinding for binaries that are created using GCC or LLVM, enable frame pointers before you compile them.
To let Streamline decide which events to capture, select Auto in the Exclude kernel events drop-down menu. If you start your capture in the Android tab in the Start view, Streamline does not capture kernel events. If you start gator manually, you can override this using the --system-wide command line option.
To capture userspace events only, and ignore kernel events, select Yes in the Exclude kernel events drop-down menu.
To capture kernel events and userspace events, select No in the Exclude kernel events drop-down menu.
To collect Ftrace data more efficiently, select Use more efficient Ftrace collection. The Live view does not update charts that use Ftrace data, but the data is in the finished report.
To set a Duration for the capture, enter the time that you want the capture session to last either in seconds or in minutes and seconds.
Enter 60 to set a capture session for 60 seconds.
Enter 1:20 to set a capture session for 1 minute 20 seconds.
If you do not enter a duration, the capture session continues until you stop it manually or, if you are not using streaming, until the buffer is full.
Click Save.