Performance of the CMS tracker in high level trigger

The Compact Muon Solenoid (CMS) detector will have a large tracking system entirely based on silicon detectors. This will be a key element for the discovery potential of the CMS experiment. The Tracker layout is presented and the performance for several benchmark topologies is discussed. In particular the CMS Tracker can provide a robust partial reconstruction using the absolute minimum number of reconstruction steps inside a region of interest, tuned according to the specific benchmark channel. Recent results have shown that the performance of partial reconstruction in terms of resolution and CPU time allows the use of the Tracker at the first stage of the High Level Trigger (HLT) on all physics events. The role of the Tracker in b and tau triggers will be also discussed.