The HEAPPOOLS summary displays a report of the HEAPPOOLS statistics and provides suggested percentages for current cell sizes as well as suggested cell sizes.
Initial Heap Size * (Extent Percent/100))/(Element Size)
To optimize storage usage, the extents allocated should be either one or two. If the number of extents allocated is too high, then increase the percentage for the pool.
A large number in this field could indicate a storage leak.
(Maximum Cells Used * (Element Size) * 100) / Initial Heap Size
With a minimum of 1% and a maximum of 90%
Make sure that your cell pool extents are neither too large nor too small. If your percentages are too large then additional, unreferenced virtual storage will be allocated, thereby causing the program to exhaust the region size. If the percentages are too small then the HEAPPOOLS algorithm will run inefficiently.
The suggested cell sizes are given with no percentages because the usage of each new cell pool size is not known. If there are less than 12 cell sizes calculated and the last calculated cell size is smaller than the largest cell size currently in effect, the largest cell size currently in effect will be used for the last suggested cell size.
For more information about stack and heap storage, see z/OS Language Environment Programming Guide .