Monitoring the responsiveness of a user interface

A diagnostic mechanism monitors execution of a user interface (UI) thread to detect execution of a long running task that may have caused the UI thread to become unresponsive. The execution time of the UI thread is monitored and when it exceeds a threshold, the UI thread's call stack is preserved to a mini-dump file. The completion time of the UI thread is also tracked and stored in a delay file. The mini-dump and delay files are then uploaded to a server where the collected data is aggregated overall execution runs by multiple users to identify the cause of the unresponsiveness.