Measuring CMS software performance in the first years of LHC collisions

The CMS software framework (CMSSW) is a modular object-oriented data analysis framework enabling the CMS collaboration to process and analyze the fast growing LHC collision data set. A software performance suite of tools has been developed and integrated in CMSSW itself to keep track of CPU time, memory footprint and event size on disk. These three metrics are key constraints in software development in order to meet the requirements considered in the planning and management of the CMS computing infrastructure. The performance suite allows the measurement and tracking of the performance across the framework, storing the results in a dedicated database. A web application is deployed to publish the results, making them easily accessible to software release managers and allowing for automatic integration in CMSSW release cycle quality assurance. The performance suite is also available to individual developers for dedicated code optimization and the web application allows historic regression and comparisons across releases. The performance suite tools and the performance of the CMSSW framework during the first LHC collisions years are described in this paper.