Least Slack First Scheduling

• Slack: Burst + Deadline –Current time
• Least slack first is optimal scheduling for meeting the deadline.
• In real time systems, the task are well behaved
  • Easier to guess the burst accurately.
  • Or, the tasks announce their burst time.

LSF Schedule

RT Scheduling

• If task declare their CPU burst
  • A task that finishes within the time is a good task.
  • A task that leaves a lot of slack is an issue and can influence the admission policy.
    • Denial of service??
• Solution: “Charge” tasks based on their declared burst.