A real-time application on the SP2
Efficient parallel algorithms together with High Speed inter processor communications are necessary to address the LHC event triggering challenge. A realistic farmbased algorithm of a part of the Second level Trigger has been successfully implemented. Preliminary measurements on a limited number of nodes (up to 13 nodes) are very encouraging, since performances are on average less than one order of magnitude lower than targeted: we indeed measured an overall frequency per event of 17 KHz instead of the 100 KHz targeted. Moreover, the conditions under which we ran the tests were not the best: with a dedicated machine for benchmarking, we can expect to increase the performance. Moreover, with the foreseen evolution of parallel machines, we can expect to pull performances quite close to the required limit of 100 KHz, and even to exceed this limit by 2004, date from which the LHC will enter on a production phase.