Update readme to reflect new traffic generator changes.

The readme was updated to reflect the new json configuration parameters
for the traffic generator.

README.md

@@ -126,8 +126,15 @@ The JSON code below shows an example configuration:
                 "name": "ddr3_example.stl"
             },
             {
-                "clkMhz": 400,
+                "clkMhz": 2000,
-                "name": "ddr3_example.stl"
+                "type": "generator",
+                "name": "gen0",
+                "numRequests": 2000,
+                "rwRatio": 0.85,
+                "addressDistribution": "random",
+                "seed": 123456,
+                "maxPendingReadRequests": 8,
+                "maxPendingWriteRequests": 8
             }
         ]	
     }
@@ -142,7 +149,14 @@ Fields Description:
 - "mcconfig": memory controller configuration file
 - "tracesetup": The trace setup is only used in standalone mode. In library mode or gem5 mode the trace setup is ignored. Each device should be added as a json object inside the "tracesetup" array. 
 
-Each **trace setup** device configuration consists of two parameters, **clkMhz** (operation frequency of the **trace player**) and a trace file **name**. Most configuration fields reference other JSON files which contain more specialized chunks of the configuration like a memory specification, an address mapping and a memory controller configuration.
+Each **trace setup** device configuration can either be a **trace player** or a **traffic generator**. By not specifing the **type** parameter, the device will act as a **trace player**.
+All device configurations must define a **clkMhz** (operation frequency of the **traffic initiator**) and a trace file **name** (in case of a trace player this specifies the **trace file** to play; in case of a traffic generator this field is only for identification purposes).
+The **maxPendingReadRequests** and **maxPendingWriteRequests** parameters define the maximum number of outstanding read/write requests. The current implementation delays all memory accesses when one limit is reached. The default value (0) disables the limit.
+
+A **traffic generator** can be configured to generate **numRequests** requests in total, of which the **rwRatio** field defines the probability of one request being a read request. The **seed** parameter can be used to produce same results for all simulations.
+The parameter **addressDistribution** can either be set to **"random"** or **"sequential"**. In case of **"sequential"** the additional **addressIncrement** field must be specified, defining the address increments after each request.
+
+Most configuration fields reference other JSON files which contain more specialized chunks of the configuration like a memory specification, an address mapping and a memory controller configuration.
 
 
 #### Trace Files