6.2.4.2 Host Validation and Ranking

Each host is registered with SIESTA by defining a performance metric w_i of its CPUs, the number of CPUs n_i^cpu, and the desired maximum load l_i^lim. A host is considered to be available if its current load does not exceed

$$l_i^{max} = \left( l_i^{lim} + l_{base} \right) + 1.0 \mbox{,}$$

where l^base denotes an amount of workload by which the limit of each individual host is increased. For each available host a ranking

$$p_i= \frac{\mbox{max}\left( 1.0 \mbox{\ ,\ } \frac{l_i^{eff}+1.0}{n_i^{cpu}} \right)} {w_i}$$ (6.1)

is computed, which is an estimate for the performance that could be obtained if a job were executed under the hosts current operating conditions. Out of all hosts that have been identified to be suitable for a simulation tool before, the one with the smallest value of p_i is selected for computation. The setting of l_base can be utilized to increase the load limits of all hosts simultaneously in situations where none of the hosts is below its load limit which might be caused by jobs of other users.