The simulator window is divided into four sections:

• Enabled transitions part is in the upper left corner showing the transitions that the system can take from the given state. You can choose the transition to be taken in the step-by-step manual simulation mode. In the random run simulation mode the transitions are randomly chosen.

• Watches part is right below Enabled transitions part. Here you can observe the values of clocks, variables as well as task and processor utilization factors at any time during simulation.

• The upper right part is displaying the Message Sequence Chart. Vertical lines correspond to the system process control flows showing their current states in rounded rectangles. Horizontal arrows are interprocess synchronizations performed via named channels.

• The lower right part is a Gantt Chart showing the timeline where you can see the tasks being executed and a processor idle time.

Times Simulator

When simulating only one execution trace within the tree is explored. On every step of simulation there can be several enabled transitions, different ways to go, due to non-determinism. These possibilities are shown in the Enabled Transitions view.

Enabled transitions

The buttons below the list of enabled transitions are used to control the simulation process and navigate through the trace being explored. There are two modes of simulation: step-by-step simulation and random run initiated by means of control buttons and correspondingly.

Simulation in step-by-step mode is performed manually by selecting one of the enabled transitions and pressing the button to make the next simulation step.
Note: When selecting an enabled transition you can see the next predicted state of the system at the bottom of the Message Sequence Chart below the violet bar drawn with brighter colors.

In the random run mode transitions are chosen randomly and the simulator continuously performs one simulation step after another. You can stop the simulation at any time by pressing the button.

When you have got a trace you can move along it back and forth in the Message Sequence Chart using and buttons. Being at any point of the trace you can observe the state of the system together with the variable values. The button moves the simulator to the end of the trace that is exlored so far. It is possible to continue simulation from any point withing the explored trace. In this case the tail of this trace will be erased.

If you press the button the simulator will reset its state to initial as if you have just started it.

In this section you can observe values of variables and clocks as simulation goes. You can choose the view to see either only clocks, only variables or both together. There is also a fourth view with two progress bars in it. The first progress bar is showing the processor utilization, i.e. how busy is the processor executing your model tasks. This is an average value taken from the beginning of the current execution trace. The second bar is showing momentary task queue utilization, i.e. how many task instances are currently in the queue relative to the queue capacity (sum of Max # of tasks parameter for all tasks).

Processor and task queue utilization

Traces in Times are represented by Message Sequence Chart (MSC), a UML-like sequence diagram showing concurrent execution of processes and their intercommunication. The MSC view is quite interactive: you can observe the whole execution trace, move to particular states in it, hide/show different processes etc.

In the Message Sequence Chart process states are hidden (replaced by a thin vertical line) if they have the same names as the name of a state since the last state change. To view the state names of all processes at a certain level of the chart move over the pointer to this level.

• Menus

  If you move the pointer over a process name in MSC header, it will become high-lighted. Right-click on it and a menu containing the following items will appear.

  • Find location...

    Allows you to find the next occurrence of the location name of the selected process in the whole trace. If location is found the MSC cursor (violer bar) jumps to it. Otherwise if the end of the trace is reached you will be asked to continue search from its beginning.

    Finding location in MSC trace

    If one occurrence of the location name was found, you can easily search for the next/previous one using menues Next 'location' and Previous 'location'.

  • Hide

    Hides the whole process substituting it with the thick red line in the MSC view. All communications between visible and hidden processes are still shown as outgoing and incoming into the red vertical line horizontal arrows. It is also possible to hide several going one after another processes into one line. Hidden processes can be shown again using menu Processes....

  • Processes...

    Opens a window where you can select which processes to show in the MSC view. Simply check the boxes of the processes you want to make visible.

    Selecting processes visible in MSC

    You can also access this menu item right-clicking at any point of the MSC header, which is useful if all the processes have been accidentially hidden.

  Gantt Chart
  This section has a form of Gantt Chart visualizing executed tasks, where the horizontal axis represents time. The top line is associated with the processor idling, i.e. blue rectanges appearing on it denote periods when the processor doesn't execute any task. On the lines below the execution of tasks is drawn. Tasks sorted on a Gantt Chart according to their priorities with the higher priority task depicted on the top line. The black up-arrow denotes a task release time, red rectangle corresponds to the task execution and the down-arrow shows that the task has finished its execution.

  Similarly to the MSC view Gantt Chart is also interactive in the sense that you can move the pointer over the timepoint you are interested in and jump to it by left-clicking. The scale of the timeline is adjustable. Use [+] and [-] buttons in the upper left corner to change the scale.

  Simulator menus
  • File
    • Close simulator

      This closes the simulator. If you just want to switch view to the editor, you should use menu Window->Editor.

  • Run
    • Syntax checking

      Performs a check of system syntax.

    • Simulation

      Starts the simulator, as described in the simulator section.

    • Schedulability analysis

      Determines whether the system is schedulable.

    • Verification

      Displays a dialog box where you can enter the system property to be verified, as described in the analysis section.

    • Code synthesis

      Generates source code, as described in the code synthesis section.

    • Compile

      Compiles generated code, as described in the code synthesis section.

  • Options
    • Configuration...

      Shows the configuration dialog box, as desribed in the configuration section.

  • Window
    • Editor

      Shows the editor window.

    • Simulator

      This option is not available in the simulator view.

    • Response times

      Shows the window with the response times resulting from the schedulability analysis.

  • Help
    • About...

      Displays the dialog box with the version, copyright notice, and a web address of the tool home Page.

See also:

Times Editor | Analysis