Evolution and performance of the ATLAS jet trigger

Jet-based trigger triggers allow the ATLAS experiment to perform an important first selection of physics events for use in studies of Standard Model processes and in searches for new physics at the LHC. The ATLAS jet trigger system has evolved substantially over the past few years of LHC operations, as experience accumulated with triggering in a high luminosity and high event pileup environment. In particular, the localised ``region-of interest'' (ROI) reconstruction strategy has been replaced by a full detector calorimeter reconstruction (``full scan'') at the third trigger level, and by a full scan of the level-1 trigger input at level-2 for some specific trigger chains. Hadronic calibration and cleaning techniques are applied in order to provide improved performance and increased stability in high luminosity data taking conditions. In this presentation we describe the structure and performance of the ATLAS jet trigger during 2011 and 2012 data taking.