The Darshan source tree is divided into two parts:

- darshan-runtime: to be installed on systems where you intend to 
  instrument MPI applications.  See darshan-runtime/doc/darshan-runtime.txt
  for installation instructions.

- darshan-util: to be installed on systems where you intend to analyze
  log files produced by darshan-runtime.  See
  darshan-util/doc/darshan-util.txt for installation instructions.

General documentation can be found on the Darshan documentation web page:
http://www.mcs.anl.gov/darshan/documentation/

The darshan-test directory contains various test harnesses, benchmarks,
patches, and unsupported utilites that are mainly of interest to Darshan
developers.