Slack scheduling for improved response times of period transformed processes

A method of allocating processor slack to periodic processes having process criticalities and deadlines, the method comprising:

• period transforming a periodic task set having at least one periodic process to produce at least one transformed periodic process each having a transformed rate, wherein a ranking of the transformed rate of each transformed periodic process corresponds to a ranking of the process criticality of each periodic process;
• assigning a slack-level to each transformed periodic process corresponding to the ranking of the transformed rates;
• assigning a slack-level to any aperiodic process, wherein the assigned slack-level for an aperiodic process equals the slack-level of a transformed periodic process having the highest process criticality not greater than the process criticality of such aperiodic process;
• and
• allocating processor slack to the transformed periodic processes in accordance with their slack-levels, wherein slack allocated at a first slack-level will not cause any periodic process having a slack-level equal to or greater than the first slack-level to miss its deadline.

A method of scheduling periodic incremental processes, comprising:

• period transforming a periodic task set having at least one periodic process to produce at least one transformed periodic process each having a transformed rate and at least one baseline component time slice, wherein a ranking of the transformed rate of each transformed periodic process corresponds to a ranking of the process criticality of each periodic process, further wherein at least one periodic process is a periodic incremental process;
• assigning a slack-level to each transformed periodic process corresponding to the ranking of the transformed rates;
• and
• allocating processor slack to baseline component time slices of the at least one periodic incremental process in accordance with the slack-levels of their corresponding transformed periodic incremental processes, wherein slack allocated at a first slack-level will not cause any periodic process having a slack-level equal to or greater than the first slack-level to miss a deadline of such periodic process.

A method of scheduling periodic incremental processes, comprising:

• period transforming a periodic task set having at least one periodic process to produce at least one transformed periodic process each having a transformed rate and at least one baseline component time slice, wherein a ranking of the transformed rate of each transformed periodic process corresponds to a ranking of the process criticality of each periodic process, further wherein at least one periodic process is a periodic incremental process;
• assigning a slack-level to each transformed periodic process corresponding to the ranking of the transformed rates;
• assigning a slack-level to any aperiodic process, wherein the assigned slack-level for an aperiodic process equals the slack-level of a transformed periodic process having the highest process criticality not greater than the process criticality of such aperiodic process;
• and
• allocating processor slack to baseline component time slices of the at least one periodic incremental process in accordance with the slack-levels of their corresponding transformed periodic incremental processes, wherein slack allocated at a first slack-level will not cause any periodic process having a slack-level equal to or greater than the first slack-level to miss a deadline of such periodic process.

A method of scheduling periodic incremental processes, comprising:

• period transforming a periodic task set having at least one periodic process to produce at least one transformed periodic process each having a transformed rate and at least one baseline component time slice, wherein a ranking of the transformed rate of each transformed periodic process corresponds to a ranking of the process criticality of each periodic process, further wherein at least one periodic process is a periodic incremental process and at least one periodic process is a design-to-time process;
• assigning a slack-level to each transformed periodic process corresponding to the ranking of the transformed rates;
• assigning a slack-level to any aperiodic process, wherein the assigned slack-level for an aperiodic process equals the slack-level of a transformed periodic process having the highest process criticality not greater than the process criticality of such aperiodic process;
• allocating all available processor slack to baseline component time slices of the at least one periodic incremental process in accordance with the slack-levels of their corresponding transformed periodic incremental processes, wherein slack allocated at a first slack-level will not cause any periodic process having a slack-level equal to or greater than the first slack-level to miss a deadline of such periodic process;
• and
• allocating unused processor slack at a slack-level to increments of transformed periodic incremental processes after completion of baseline components of such transformed periodic incremental processes.