Graphics, Windowing, and Events Subsystem Considerations (Windows CE 5.0)
Making Graphics, Windowing, and Events Subsystem (GWES) API calls in the thread that requires a real-time response can worsen real-time performance. GWES provides the functionality needed to display windows, draw objects, and enable notifications. However, this functionality has no guaranteed latency. Because GWES utilizes a single critical section to protect access to its internal data structures, a thread can be blocked for an unbounded length of time while it waits for another thread to complete an operation.
Using SetTimer as a real-time timer can also worsen performance. SetTimer is a timer based on Windows CE message queues that has no guarantee for signaling time.
GWES can also worsen performance through its use of display drivers. For more information, see Display Drivers.
See Also
Real-Time Performance Considerations
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