gpuStartTime
The host time, in seconds, when the GPU starts command buffer execution.
Declaration
var gpuStartTime: CFTimeInterval { get }Discussion
You can calculate how much time the GPU spends running a command buffer by subtracting this value from gpuEndTime. Both values are relative to system mach time.
The GPU start and end times remain 0.0 until the GPU finishes running the command buffer. Check this value after the waitUntilCompleted() method returns, or within a completion handler passed to the addCompletedHandler(_:) method.