# Performance measurement `onetick.py` and OneTick provide some tools and classes to run the query and measure its performance. ## measure_perf.exe Function [`onetick.py.perf.measure_perf()`](../../api/performance.md#onetick.py.perf.measure_perf) can be used to call OneTick's **measure_perf.exe** tool. It runs specified query and prints the summary in the specified file. ## Parsing summary Classes [`onetick.py.perf.PerformanceSummaryFile`](../../api/performance.md#onetick.py.perf.PerformanceSummaryFile) and [`onetick.py.perf.MeasurePerformance`](../../api/performance.md#onetick.py.perf.MeasurePerformance) can be used to parse contents of the summary file to python format. Additionally, configuration parameter `stack_info` can be used to add some python debug information to the parsed result. ## Session metrics You can also gather performance metrics for all queries made in a session. To do this, set `gather_performance_metrics` parameter to `True` when creating an [`otp.Session`](../../api/session/session.md#onetick.py.Session) object. Metrics could be accessed after session close via `otp.Session.performance_metrics` property. Example of collecting performance metrics, returned data format and information about limitations you can find in the [`otp.Session`](../../api/session/session.md#onetick.py.Session) documentation.