1. A method, comprising: determining computational resource capacity characteristics from historical usage data relating to use of a heterogeneous inventory of computational resources, the computational resource capacity characteristics comprising a trace history representative of the availability of various components of the heterogeneous inventory of computational resources at various points in time; calculating a plurality of finishing times for a project by performing a plurality of simulation runs based on the computational resource capacity characteristics, wherein each of the plurality of simulation runs begins at a different time in the trace history; assembling the plurality of finishing times into a distribution; constructing a risk measure using the distribution; and facilitating selection of a portfolio for the project from the heterogeneous inventory of computational resources based on the risk measure and the plurality of finishing times.