QDIME: QoS-aware Dynamic Binary Instrumentation

Software systems with quality of service (QoS), such as database management systems and web servers, are ubiquitous. Such systems must meet strict performance requirements. Instrumentation is a useful technique for the analysis and debugging of QoS systems. Dynamic binary instrumentation (DBI) extracts runtime information to comprehend system's behavior and detect performance bottlenecks. However, existing DBI tools are intrusive; adding unacceptable delay to the program execution. Such delay alters the performance requirements and degrades the overall quality and the user experience of the system. Moreover, the delay may change the system behavior, thus, producing misleading run-time information. 
 This paper presents QDIME, a QoS-aware dynamic binary instrumentation technique that respects system's performance requirements. QDIME takes a user-defined QoS threshold as an input and periodically gathers QoS feedback from the system under analysis to decide its instrumentation budget. 
 We implemented QDIME on top of PIN, a popular DBI framework. We evaluated QDIME with Gzip, MySQL server, Apache HTTP server, and Redis. The experiments show that QDIME respects the user-defined QoS threshold and, thus, improves the performance of the monitored application by manifolds. QDIME is able to provide up to 100% instrumentation coverage with an average of 92% when compared to PIN. Moreover, QDIME reduces the slow-down factor of the instrumented application by 1.41, 5.67, and 10.26 folds for Sys-trace, Call-trace, and Branch-profile respectively. A release of QDIME is available for down- load at https://github.com/pansy-arafa/qdime