The Application Monitor (APIMON.EXE) counts and times all Win32 function calls. It can optionally monitor page faults caused by the monitored application and report them by Win32 function call. This tool is included in the Platform SDK.
APIMON is a performance monitor that can help you tune your application. The data can be used to determine the Win32 functions that have the largest times and counts. APIMON generates two types of reports: a report containing all calls, showing their counts and times, and a report showing a trace of all calls as they occurred.
For more information, see APIMON.HLP, which is included in the Platform SDK.