doc the jobmap api

doc/GETTING_STARTED

@@ -164,6 +164,15 @@ should be everything up to the rank number. E.g., if the dumpi files are of the
 form "dumpi-YYYY.MM.DD.HH.MM.SS-XXXX.bin", then the input should be
 "dumpi-YYYY.MM.DD.HH.MM.SS-"
 
+=== Workload generator helpers
+
+The codes-jobmap API (codes/codes-jobmap.h) specifies mechanisms to initialize
+and run multiple jobs with unique job IDs and linear namespaces, used to allow
+multiple concurrent workloads to be run within the same simulation. Example
+usage can be seen in tests/jobmap-test.c and, for the list allocation method,
+in tests/conf/jobmap-test-list.conf. Note that only the DUMPI trace generator
+has been tested using this interface at this time.
+
 == LP-IO
 
 LP-IO is a set of simple reverse-computation-aware routines for conditionally