  The Muon Spectrometer (MS) of the ALICE experiment at LHC is equipped with a
HLT (High Level Trigger), whose aim is to improve the accuracy of the trigger
cuts delivered at the L0 stage. A computational challenge of real-time event
reconstruction is satisfied to achieve this software trigger cut of the HLT.
After the description of the online algorithms, the performance of the online
tracker is compared with that of the offline tracker using the measured pp
collisions at $\sqrt{s}=7$ TeV.
