hdf5_msb

[svn-r9687] Purpose:

   Modify the cache code (H5C) to support automatic cache resizing to
adapt to the work load at run time.


Description:

   Different applications require different sized caches to maintain
an acceptable hit rate.  This set of changes attempts to provide the
ability to adjust to circumstances automatically.


Solution:

   Added highly configurable code to allow the user to either set a
fixed cache size, or allow the cache to grow and shrink according to
conditions.

   If enabled, cache size increases are triggered when the hit rate
drops below a user specified threshold in a user specified interval.

   Cache size reductions (if enabled) are triggered when either the
hit rate exceeds some user specified threshold over a user specified
interval, when the cache contains "enough" entries that haven't been
accessed for a user specified interval, or some mix of the above.

   See the header comments on the H5C_auto_size_ctl_t structure in
H5Cprivate.h for further details.

   At present, the cache resize configuration options are not
accessible via the user API.  Must add this.


Platforms tested:

   h5committested, heping (serial), and copper (parallel)


Misc. update: