benchtests/README update.

Improve documentation of the 'name' directive and the 'workload' mechanism.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

benchtests/README

@@ -125,17 +125,25 @@ math functions perform computations at different levels of precision (64-bit vs
 performance of these functions.  One could separate inputs for these domains in
 the same file by using the `name' directive that looks something like this:
 
-  ##name: 240bit
+  ##name: 240bits
 
-See the pow-inputs file for an example of what such a partitioned input file
-would look like.
+All inputs after the ##name: 240bits directive and until the next `name'
+directive (or the end of file) are part of the "240bits" benchmark and
+will be output separately in benchtests/bench.out.  See the pow-inputs file
+for an example of what such a partitioned input file would look like.
 
-It is also possible to measure throughput of a (partial) trace extracted from
-a real workload.  In this case the whole trace is iterated over multiple times
-rather than repeating every input multiple times.  This can be done via:
+It is also possible to measure latency and reciprocal throughput of a
+(partial) trace extracted from a real workload.  In this case the whole trace
+is iterated over multiple times rather than repeating every input multiple
+times.  This can be done via:
 
   ##name: workload-<name>
 
+where <name> is simply used to distinguish between different traces in the
+same file.  To create such a trace, you can simply extract using printf()
+values uses for a specific application, or generate random values in some
+interval.  See the expf-inputs file for an example of this workload mechanism.
+
 Benchmark Sets:
 ==============