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The trigger systems of the LHC detectors play a crucial role in determiningthe physics capabilities of the experiments. A reduction of several orders ofmagnitude of the event rate is needed to reach values compatible with thedetector readout, offline storage and analysis capabilities. The CMS experimenthas been designed with a two-level trigger system: the Level 1 (L1) Trigger,implemented on custom-designed electronics, and the High Level Trigger (HLT), astreamlined version of the CMS reconstruction and analysis software running ona computer farm. The software-base HLT requires a trade-off between thecomplexity of the algorithms, the sustainable output rate, and the selectionefficiency. This is going to be even more challenging during Run II, with ahigher centre-of-mass energy, a higher instantaneous luminosity and pileup, andthe impact of out-of-time pileup due to the 25 ns bunch spacing. The onlinealgorithms need to be optimised for such a complex environment in order to keepthe output rate under control without impacting the physics efficiency of theonline selection. Tracking, for instance, will play an even more important rolein the event reconstruction. In this poster we will present the performance ofthe online track and vertex reconstruction algorithms, and their impact on thehadronic triggers that make use of b-tagging and of jets reconstructed with theParticle Flow technique. We will show the impact of these triggers on physicsperformance of the experiment, and the latest plans for improvements in view ofthe Run II data taking in 2015.

Performance of the online track reconstruction and impact on hadronic triggers at the CMS High Level Trigger