ATLAS online data quality monitoring

With the delivery of the first proton-proton collisions by the LHC, the ATLAS collaboration had the opportunity to operate the detector under a closer environment to what it was designed for. These first events have been of great interest not only for the high energy physics outcome, but also as a means to perform a general commissioning of the entire system, and in particular, of a highly scalable distributed monitoring framework that assesses the quality of the data and the operational conditions of the detector, trigger and data acquisition system. Every minute of an ATLAS data taking session the monitoring framework serves several thousands of physics events to the monitoring data analysis applications and handles millions of histogram updates coming from many different applications. This framework also executes over forty thousand advanced data quality checks for a subset of those histograms and displays those histograms together with the results of all those checks on several dozens of monitors installed in main and satellite ATLAS control rooms. The online data quality monitoring system has been of great help in providing quick feedback to the different experts about the functioning and performance of the subsystems those experts are responsible for by providing an easy and fast configurable visualization of all this information. The Data Quality Monitoring Display (DQMD) is the visualization tool for the automatic data quality assessment. It is the interface through which the shift crew and the experts can validate the quality of the data being recorded or processed, be warned of problems related to data quality, and identify the origin of such problems. The display is designed to work both online within the trigger and data acquisition (tdaq) environment, offline at the various tiers for processing of data, or privately by experts. This tool allows great flexibility for visualization of histograms, with an overlay of reference histograms when applicable, co- - nfigurations used for automatic checking of those histograms, and the results. The display configuration is stored in a database, that can be easily created and edited with the Data Quality Monitoring Configurator (DQMC) tool. The first weeks of collisions data taking turned into a very successful experience for the monitoring framework and translated into several improvements to easy usability and efficient information transfer. A description of the design and implementation of the DQMD and DQMC will be presented, as well as the performance of the monitoring framework during the first ATLAS run and the recent upgrades concerning alarm handling and parameters finding.