Adaptive scheduling to maintain smooth frame rate

Abstract

Described is an adaptive scheduler associated with a desktop window manager that dynamically controls the rate at which graphics frames are composed. Values corresponding to performance when composing a frame are measured, and the frame composition rate is adjusted as necessary based on the values. The measured data is sampled to provide smooth adjustments. The sampled data is evaluated as to whether the current frame rate is too slow, too fast, or acceptable. If too slow, the frame rate may increased relative to the refresh rate, while if too fast, the frame rate is decreased relative to the refresh rate. In one implementation, the frame rate is too fast if a count of missed frames achieves a missed threshold value, or if a count of late frames achieves a late threshold value. The frame rate is too slow if a count of early frames exceeds an early threshold value.