Measuring Timer Latencies

The RTX Runtime provides a utility called System Response Time Measurement (SRTM), a real-time API timer latency measurement tool that measures timer latency observed by an application. Each of the two supplied versions of SRTM, Win32 and RTSS, measures its own environment. An SRTM histogram often shows a characteristic double peak profile: the first peak is a near-best case; the second is the dirty-cache case. The diagram occasionally shows additional smaller spikes from processor-level interrupt masking.

By default, this tool generates a 15-second tone and prints a histogram of timer response latencies. You can run SRTM in the RTSS environment to measure RTSS latencies.

To measure timer latency, type the following at a command prompt:

RTSSrun "c:\program files\IntervalZero\rtx\bin\srtm.rtss" [-h][-s][-1][f] seconds_to_sample