The tool has been developed to to explain how Dynamic Voltage scaling works. The basic setup requires the user to enter the parameters of various tasks which includes Period, Worst Case Execution time and Actual Execution Time. The processor parameters such as the Frequency and the corresponding Voltages can also be entered by the user. For the uninitiated, the tool comes with default values so the the user is not required to enter the values manually. However, these values can be edited in the respective textboxes.
The interface basically consists of two tables :
1. Processor Parameters - The user can either use the default values for the Relative Frequency and Voltage or enter values manually. A maximum of 5 values can be entered. The Reset button can be used to revert back to the default values.
2. Task Parameters - This table consists of three parameters - Period, Worst Case Computation Time and Actual Execution Time. Again, the user can either use the default values for the three parameters for each task or enter values manually. Also note that, less than six tasks can be entered. The Simulate button takes the user to the Output page wherein the time line graph for each algorithm is displayed for every task entered by the user.
The output shows whether the entered task set is schedulable or not. If it is, whether it is RM Schedulable or EDF schedulable or both.
The time line graph of every task for every algorithm is also output. Observe that every task shows a maximum of 11 iterations. The task is assumed to repeat the pattern after the 11 iterations and is thus not included in the time line graph. Below the graph for every task, you will find the parameters of that task namely, Release time, Voltage and the Frequency.
Release time - The time when the task was invoked and the actual execution of the task began.
Voltage - The scaled voltage for that particular task. This voltage depends on the particular taskset and the algorithm used and is thus not constant.
Frequency - The corresponding scaled frequency for that task set.
Energy Savings :
The Normalised energy consumed by the taskset compared to the non-DVS algorithms is displayed here.
Example Test cases :
You will find some example testcases here if you are unsure of what the task parameters should be.