Workload Capture & Replay

The simulation of load situations under real conditions is an important capability that makes it possible to test and optimize modules and improve performance.

"Workload Capture & Replay" provides functions which allow you, for example, to compare identical UTM applications from different openUTM versions or perform comparative measurement on different computer hardware variants. The Replay capability even makes it possible to compare different system platforms. Of particular importance is the ability to control the simulation of predicted higher future loads by simply adjusting the scaling parameters during replay.

Workload Capture & Replay is available for application loads that were generated by UPIC clients without encryption.

Process steps during Workload Capture & Replay

Workload Capture & Replay is performed in the following steps:

1. UPIC Capture
   Communication between the UTM application and the UPIC clients is recorded during live application operation. To do this, UTM uses trace functions and the recording is available in the form of trace files that are local to the process.

2. Trace merging
   The recording of all the UTM processes is now sorted and entered in a file in the precise chronological order.

3. UPIC Analyzer
   The sorted recording is analyzed using the program UpicAnalyzer. This results in the generation of a file in UPIC Replay Format.

4. UPIC Replay
   The file in UPIC Replay Format is used as the input for the UPIC-based load driver program UpicReplay. During the load test, the recorded UPIC conversations are automatically repeated in the correct chronological order. To simulate different loads, scaling parameters can be adjusted to vary the number of UPIC clients that are active in parallel and the thinking time per client.

   For the replay operation, the load, and therefore also the throughput, can be set to be several times greater than during recording. This replay operation is reproducible and can be repeated multiple times in order, for example, to examine the behavior of the UTM application at different load factors.

The programs UpicAnalyzer and UpicReplay run on 64-bit Linux systems.