2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/5498I describe here the performances of a parallel treecode with individual particle timesteps. The code is based on the Barnes-Hut algorithm and runs cosmological N-body simulations on parallel machines with a distributed memory architecture using the MPI message passing library. For a configuration with a constant number of particles per processor the scalability of the code has been tested up to P=32 processors. The average CPU time per processor necessary for solving the gravitational interactions is within $\sim 10 %$ of that expected from the ideal scaling relation. The load balancing efficiency is high ($\simgt90%$) if the processor domains are determined every large timestep according to a weighting scheme which takes into account the total particle computational load within the timestep.10 pages, 3 figures in "Computational astrophysics in Italy: methods and tools'', Bologna, July 4-5, 2002, Ed R. Capuzzo DolcettaAstrophysicstext