Lin Xu writes:
 > 
 > We are running ACL 6.2 on Sun OS and wonder what we are wrong..
 > 
 > Our implementation relies on storing data in hash-tables.  We do not
 > know a priori the number of data items to be stored (could vary from
 > 20 data items to 60,000 even more).
 > 
 > We noticed (with profiler) that, with a fixed hash-table size, much
 > effort is spent on (re-)hashing.  So, we tried to declare the size of
 > the hashtable as some function of the input parameters.  We use the
 > following rehash arguments :rehash-threshold 0.9 :rehash-size 1.5.

Are you using EQ or EQUAL hashtables?  If EQ hashtables, it might
be you are losing due to gsgc.  EQ hashtables hash on address
and therefore have to be rehashed whenever the elements are
moved due to gsgc.  That would also explain the erratic behavior
you mention.

/Eric M/
Reasoning, Inc