Build_driver is used to measure the performance of the heap building process. It generates MAXSZ elements according to the parameters and repeatedly calls method bulk_insert of an empty heap until all the data is used.
Data alignment can be controlled by the align/noalign parameter, but for the alignment to be effective, the heap size used must be divisible by the cache line size. Alignment is done according to the specifications in chapter 5. For some heap implementations alignment is important for the performance.
Timings are reported as ms per element in a format suitable for gnuplot.