Performance of the ATLAS Tau Trigger system with 7 TeV pp collisions at the LHC

The LHC has started operation and roughly provided 60 nb^{-1} of 7 TeV proton-proton collisions in the period March-June 2010. These data have been used to understand the performance of the ATLAS experiment, and in particular, of the tau trigger system. The tau trigger is a key element in the discovery of new physics, where tau lepton final states play a crucial role. It allows efficient collection of the physics signal, while keeping the rate of background events within the allowed bandwidth. During 2010 it has been commissioned in various stages. At first, the hardware-based first level trigger (L1) was used to select interesting high p_{T} physics samples. During this period the Higher Level Trigger (HLT) was running online, but not rejecting any events. This stage has allowed to study in detail the HLT performance before activation. At a later time, when the luminosity was high enough that the L1 trigger alone could not reject anymore events without affecting the collection of interesting physics, the HLT active selection online has begun. This contribution will summarize the status of the tau trigger system at the different stages of data taking, emphasizing the key elements of the online selection and their performance. Methods for obtaining trigger efficiency curves from data will be shown and first results presented. The strategy for ensuring measurements of Standard Model and new physics will be outlined, in light of t he recent real data results.