1. USC Viterbi School of Engineering Ewa Deelman Resource Management

2. USC Viterbi School of Engineering Runtime-based Scheduling Priority Queue Phase –Eligible jobs are determined – based on fairness, system limitations, job state, etc... –The list of eligible jobs is then sorted by job priority and jobs are scheduled to run until a job cannot be scheduled due to resource limitations –Resources and start/end times are reserved for the first job that could not be scheduled Backfill Scheduling Phase –Jobs following the reserved job which would not delay the reserved job are scheduled on the remaining idle rsources

3. USC Viterbi School of Engineering Single Queue Backfilling A job is allowed to jump in the queue ahead of jobs that are delayed due to lack of resources Non-preemptive Conservative backfilling –A job is allowed to jump ahead provided it does not delay any previous job in the queue Aggressive backfilling –A job is allowed to jump ahead if the first job is not affected –Better performing then conservative backfilling

4. USC Viterbi School of Engineering Aggressive backfilling Job (arrival time, number of procs, expected runtime)‏ Any job that executes longer than expected runtime is killed Define pivot—first job in the queue If enough resources for pivot, execute pivot and define a new pivot Otherwise sort all currently executing jobs in order of their expected completion time –Determine pivot time—when sufficient resources for pivot are available

5. USC Viterbi School of Engineering Aggressive backfilling At pivot time, any idle processors not required for pivot job are defined as extra processors The scheduler searches for the first queued job that –Requires no more than the currently idle processors and will finish by the pivot time, or –Requires no more than the minimum currently idle processors and the extra processors Once a job becomes a pivot, it cannot be delayed Possible that a job will end sooner and pivot starts before pivot time

6. USC Viterbi School of Engineering Aggressive backfilling example Job A (10 procs,40mins)‏ 8 time Queue Job B (12 procs, 1 hour)‏ Job C (20 procs, 2 hours)‏ Job D (2 procs, 50 mins)‏ Job E (6 procs, 1 hour)‏ Job F (4 procs, 2 hours)‏ 10 processors Running Job A(10 procs, 40 mins)‏

7. USC Viterbi School of Engineering Aggressive backfilling example Job A (10 procs,40mins)‏ 8 time queue Job B (12 procs, 1 hour)‏ Job C (20 procs, 2 hours)‏ Job E (6 procs, 1 hour)‏ Job F (4 procs, 2 hours)‏ 10 processors PIVOT Job B JOB D Running Job A(10 procs, 40 mins)‏ Job D (2 procs, 50 mins)‏

8. USC Viterbi School of Engineering Aggressive backfilling example Queue Job B (12 procs, 1 hour)‏ Job C (20 procs, 2 hours)‏ Job E (6 procs, 1 hour)‏ Job A (10 procs,40mins)‏ 8 time 10 processors PIVOT Job B Job D Running Job A(10 procs, 40 mins)‏ Job D (2 procs, 50 mins)‏ Job F (4 procs, 2 hours)‏ Job F

9. USC Viterbi School of Engineering Aggressive backfilling example Queue Job C (20 procs, 2 hours)‏ Job E (6 procs, 1 hour)‏ Job A (10 procs,40mins)‏ 8 time 10 processors Job B Job D Job F Running Job D (2 procs, 50 mins)‏ Job F (4 procs, 2 hours)‏ Job B (12 procs, 1 hour)‏

10. USC Viterbi School of Engineering Aggressive backfilling example Queue Job C (20 procs, 2 hours)‏ Job E (6 procs, 1 hour)‏ Job A (10 procs,40mins)‏ 8 time 10 processors Job B Job D Job F Running Job D (2 procs, 50 mins)‏ Job F (4 procs, 2 hours)‏ Job B (12 procs, 1 hour)‏ Pivot Job C (20 procs, 2 hours)‏