Set the average weight of an entry. This is used, together with the
maximum weight, to calculate the length of the internal array of the
For higher performance, the weight should be set relatively low, at
the cost of some space. To save space, the average weight should be
set high, at the cost of some performance.
How many other item are to be moved to the top of the stack before
the current item is moved. The default is 16. Using higher values
will avoid re-ordering in many cases, so less time is spent
reordering. But this somewhat reduces cache hit rate, and eviction
will become more random. Typically, cache hit rate can be improved by
using smaller values, and access performance can be improved using
larger values. Using values larger than 128 is not recommended.