class EasyBackfillScheduler(Scheduler):
def __init__(self, num_processors):
super(EasyBackfillScheduler, self).__init__(num_processors)
self.cpu_snapshot = CpuSnapshot(num_processors)
self.unscheduled_jobs = []
def new_events_on_job_submission(self, just_submitted_job, current_time):
""" Here we first add the new job to the waiting list. We then try to schedule
the jobs in the waiting list, returning a collection of new termination events """
# TODO: a probable performance bottleneck because we reschedule all the
# jobs. Knowing that only one new job is added allows more efficient
# scheduling here.
#print 'User submits', just_submitted_job
self.cpu_snapshot.archive_old_slices(current_time)
self.unscheduled_jobs.append(just_submitted_job)
#print 'At time', current_time, 'unscheduled:', self.unscheduled_jobs
return [
JobStartEvent(current_time, job)
for job in self._schedule_jobs(current_time)
]
def new_events_on_job_termination(self, job, current_time):
""" Here we first delete the tail of the just terminated job (in case it's
done before user estimation time). We then try to schedule the jobs in the waiting list,
returning a collection of new termination events """
self.cpu_snapshot.archive_old_slices(current_time)
self.cpu_snapshot.delTailofJobFromCpuSlices(job)
return [
JobStartEvent(current_time, job)
for job in self._schedule_jobs(current_time)
]
def _schedule_jobs(self, current_time):
"Schedules jobs that can run right now, and returns them"
jobs = self._schedule_head_of_list(current_time)
jobs += self._backfill_jobs(current_time)
#print 'Currently schedulable jobs:', jobs
#print 'Currently schedulable jobs count:', len(jobs)
self.totalScheduledJobs += len(jobs)
return jobs
def _schedule_head_of_list(self, current_time):
result = []
while True:
if len(self.unscheduled_jobs) == 0:
break
# Try to schedule the first job
if self.cpu_snapshot.free_processors_available_at(current_time) >= self.unscheduled_jobs[0].num_required_processors:
job = self.unscheduled_jobs.pop(0)
self.cpu_snapshot.assignJob(job, current_time)
result.append(job)
else:
# first job can't be scheduled
break
return result
def _backfill_jobs(self, current_time):
"""
Find jobs that can be backfilled and update the cpu snapshot.
"""
if len(self.unscheduled_jobs) <= 1:
return []
result = []
tail_of_waiting_list = list_copy(self.unscheduled_jobs[1:])
for job in tail_of_waiting_list:
if self.canBeBackfilled(job, current_time):
self.unscheduled_jobs.remove(job)
self.cpu_snapshot.assignJob(job, current_time)
result.append(job)
return result
def canBeBackfilled(self, second_job, current_time):
assert len(self.unscheduled_jobs) >= 2
assert second_job in self.unscheduled_jobs[1:]
if self.cpu_snapshot.free_processors_available_at(current_time) < second_job.num_required_processors:
return False
first_job = self.unscheduled_jobs[0]
temp_cpu_snapshot = self.cpu_snapshot.copy()
temp_cpu_snapshot.assignJobEarliest(first_job, current_time)
# if true, this means that the 2nd job is "independent" of the 1st, and thus can be backfilled
return temp_cpu_snapshot.canJobStartNow(second_job, current_time)
class EasyBackfillScheduler(Scheduler):
def __init__(self, num_processors):
super(EasyBackfillScheduler, self).__init__(num_processors)
self.cpu_snapshot = CpuSnapshot(num_processors)
self.unscheduled_jobs = []
def new_events_on_job_submission(self, just_submitted_job, current_time):
""" Here we first add the new job to the waiting list. We then try to schedule
the jobs in the waiting list, returning a collection of new termination events """
# TODO: a probable performance bottleneck because we reschedule all the
# jobs. Knowing that only one new job is added allows more efficient
# scheduling here.
self.cpu_snapshot.archive_old_slices(current_time)
self.unscheduled_jobs.append(just_submitted_job)
return [
JobStartEvent(current_time, job)
for job in self._schedule_jobs(current_time)
]
def new_events_on_job_termination(self, job, current_time):
""" Here we first delete the tail of the just terminated job (in case it's
done before user estimation time). We then try to schedule the jobs in the waiting list,
returning a collection of new termination events """
self.cpu_snapshot.archive_old_slices(current_time)
self.cpu_snapshot.delTailofJobFromCpuSlices(job)
return [
JobStartEvent(current_time, job)
for job in self._schedule_jobs(current_time)
]
def _schedule_jobs(self, current_time):
"Schedules jobs that can run right now, and returns them"
jobs = self._schedule_head_of_list(current_time)
jobs += self._backfill_jobs(current_time)
return jobs
def _schedule_head_of_list(self, current_time):
result = []
while True:
if len(self.unscheduled_jobs) == 0:
break
# Try to schedule the first job
if self.cpu_snapshot.free_processors_available_at(
current_time
) >= self.unscheduled_jobs[0].num_required_processors:
job = self.unscheduled_jobs.pop(0)
self.cpu_snapshot.assignJob(job, current_time)
result.append(job)
else:
# first job can't be scheduled
break
return result
def _backfill_jobs(self, current_time):
"""
Find jobs that can be backfilled and update the cpu snapshot.
"""
if len(self.unscheduled_jobs) <= 1:
return []
result = []
tail_of_waiting_list = list_copy(self.unscheduled_jobs[1:])
for job in tail_of_waiting_list:
if self.canBeBackfilled(job, current_time):
self.unscheduled_jobs.remove(job)
self.cpu_snapshot.assignJob(job, current_time)
result.append(job)
return result
def canBeBackfilled(self, second_job, current_time):
assert len(self.unscheduled_jobs) >= 2
assert second_job in self.unscheduled_jobs[1:]
if self.cpu_snapshot.free_processors_available_at(
current_time) < second_job.num_required_processors:
return False
first_job = self.unscheduled_jobs[0]
temp_cpu_snapshot = self.cpu_snapshot.copy()
temp_cpu_snapshot.assignJobEarliest(first_job, current_time)
# if true, this means that the 2nd job is "independent" of the 1st, and thus can be backfilled
return temp_cpu_snapshot.canJobStartNow(second_job, current_time)
