An important step before adopting a simulator is its validation, in order to determine how accurate the simulator is compared to a real machine. When validating a simulator, errors in simulating full applications can lead to misleading conclusions. In this paper, an extension of the existing tracing tool of the COTSon simulation framework is presented with the capabilities to collect information about the executed instructions from both timing and functional execution (e.g., timestamp, latency). The output trace has been compared with the assembly representation of the benchmark executed into the COTSon simulator to verify the correct execution flow. Thanks to the tracing tools, we were able to analyze the behavior of COTSon simulator during the execution of benchmarks and discover possible bottlenecks and optimization points.