1. A method, implemented by a computing system, comprising: issuing, by a first application executing on the computing system, a request for performance data of at least one second application to an operating system executing on the computing system, the request indicating one or more events to be monitored during execution of the second application, wherein the first application and the second application are running on top of the operating system; receiving, by the first application, one or more file descriptors for the events; obtaining, by the first application and during execution of the second application, current performance data of the second application using the file descriptors; utilizing, by the first application, the current performance data to determine, during execution of the second application, a list of functions performed by the second application and a number of events occurred during execution of each function in the list of functions; presenting, by the first application, resulting data to a user of the computing system, the resulting data comprising the list of functions and corresponding numbers of events; and periodically refreshing, by a processing device executing the first application and during execution of the second application, the presented data using up-to-date performance data of the second application, wherein the up-to-date performance data of the second application is obtained by the first application while the first application and the second application are running on top of the operating system.