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Move lookback limit into the QueuedJobsIterator #4003

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ea8c81a
move lookback limit to the queue iterator
d80tb7 Oct 12, 2024
1b4b93b
move lookback limit to the queue iterator
d80tb7 Oct 12, 2024
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26 changes: 19 additions & 7 deletions internal/scheduler/scheduling/jobiteration.go
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package scheduling

import (
"math"
"sync"

"golang.org/x/exp/slices"
Expand Down Expand Up @@ -110,16 +111,23 @@ func (repo *InMemoryJobRepository) GetJobIterator(queue string) JobContextIterat

// QueuedJobsIterator is an iterator over all jobs in a queue.
type QueuedJobsIterator struct {
jobIter jobdb.JobIterator
pool string
ctx *armadacontext.Context
jobIter jobdb.JobIterator
pool string
maxLookback uint
jobsSeen uint
ctx *armadacontext.Context
}

func NewQueuedJobsIterator(ctx *armadacontext.Context, queue string, pool string, repo JobRepository) *QueuedJobsIterator {
func NewQueuedJobsIterator(ctx *armadacontext.Context, queue string, pool string, maxLookback uint, repo JobRepository) *QueuedJobsIterator {
if maxLookback == 0 {
maxLookback = math.MaxUint
}
return &QueuedJobsIterator{
jobIter: repo.QueuedJobs(queue),
pool: pool,
ctx: ctx,
jobIter: repo.QueuedJobs(queue),
pool: pool,
maxLookback: maxLookback,
jobsSeen: 0,
ctx: ctx,
}
}

Expand All @@ -129,11 +137,15 @@ func (it *QueuedJobsIterator) Next() (*schedulercontext.JobSchedulingContext, er
case <-it.ctx.Done():
return nil, it.ctx.Err()
default:
if it.jobsSeen >= it.maxLookback {
return nil, nil
}
job, _ := it.jobIter.Next()
if job == nil {
return nil, nil
}
if slices.Contains(job.Pools(), it.pool) {
it.jobsSeen++
return schedulercontext.JobSchedulingContextFromJob(job), nil
}
}
Expand Down
17 changes: 9 additions & 8 deletions internal/scheduler/scheduling/jobiteration_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ package scheduling

import (
"context"
"math"
"testing"
"time"

Expand Down Expand Up @@ -64,7 +65,7 @@ func TestMultiJobsIterator_TwoQueues(t *testing.T) {
ctx := armadacontext.Background()
its := make([]JobContextIterator, 3)
for i, queue := range []string{"A", "B", "C"} {
it := NewQueuedJobsIterator(ctx, queue, testfixtures.TestPool, repo)
it := NewQueuedJobsIterator(ctx, queue, testfixtures.TestPool, math.MaxUint, repo)
its[i] = it
}
it := NewMultiJobsIterator(its...)
Expand Down Expand Up @@ -93,7 +94,7 @@ func TestQueuedJobsIterator_OneQueue(t *testing.T) {
expected = append(expected, job.Id())
}
ctx := armadacontext.Background()
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, repo)
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, math.MaxUint, repo)
actual := make([]string, 0)
for {
jctx, err := it.Next()
Expand All @@ -115,7 +116,7 @@ func TestQueuedJobsIterator_ExceedsBufferSize(t *testing.T) {
expected = append(expected, job.Id())
}
ctx := armadacontext.Background()
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, repo)
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, math.MaxUint, repo)
actual := make([]string, 0)
for {
jctx, err := it.Next()
Expand All @@ -137,7 +138,7 @@ func TestQueuedJobsIterator_ManyJobs(t *testing.T) {
expected = append(expected, job.Id())
}
ctx := armadacontext.Background()
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, repo)
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, math.MaxUint, repo)
actual := make([]string, 0)
for {
jctx, err := it.Next()
Expand All @@ -164,7 +165,7 @@ func TestCreateQueuedJobsIterator_TwoQueues(t *testing.T) {
repo.Enqueue(job)
}
ctx := armadacontext.Background()
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, repo)
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, math.MaxUint, repo)
actual := make([]string, 0)
for {
jctx, err := it.Next()
Expand All @@ -187,7 +188,7 @@ func TestCreateQueuedJobsIterator_RespectsTimeout(t *testing.T) {
ctx, cancel := armadacontext.WithTimeout(armadacontext.Background(), time.Millisecond)
time.Sleep(20 * time.Millisecond)
defer cancel()
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, repo)
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, math.MaxUint, repo)
job, err := it.Next()
assert.Nil(t, job)
assert.ErrorIs(t, err, context.DeadlineExceeded)
Expand All @@ -205,7 +206,7 @@ func TestCreateQueuedJobsIterator_NilOnEmpty(t *testing.T) {
repo.Enqueue(job)
}
ctx := armadacontext.Background()
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, repo)
it := NewQueuedJobsIterator(ctx, "A", testfixtures.TestPool, math.MaxUint, repo)
for job, err := it.Next(); job != nil; job, err = it.Next() {
require.NoError(t, err)
}
Expand Down Expand Up @@ -266,7 +267,7 @@ func (repo *mockJobRepository) Enqueue(job *jobdb.Job) {
}

func (repo *mockJobRepository) GetJobIterator(ctx *armadacontext.Context, queue string) JobContextIterator {
return NewQueuedJobsIterator(ctx, queue, testfixtures.TestPool, repo)
return NewQueuedJobsIterator(ctx, queue, testfixtures.TestPool, math.MaxUint, repo)
}

func jobFromPodSpec(queue string, req *schedulerobjects.PodRequirements) *jobdb.Job {
Expand Down
3 changes: 1 addition & 2 deletions internal/scheduler/scheduling/preempting_queue_scheduler.go
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Original file line number Diff line number Diff line change
Expand Up @@ -469,7 +469,6 @@ func addEvictedJobsToNodeDb(_ *armadacontext.Context, sctx *schedulercontext.Sch
gangItByQueue[qctx.Queue] = NewQueuedGangIterator(
sctx,
inMemoryJobRepo.GetJobIterator(qctx.Queue),
0,
false,
)
}
Expand Down Expand Up @@ -511,7 +510,7 @@ func (sch *PreemptingQueueScheduler) schedule(ctx *armadacontext.Context, inMemo
if jobRepo == nil || reflect.ValueOf(jobRepo).IsNil() {
jobIteratorByQueue[qctx.Queue] = evictedIt
} else {
queueIt := NewQueuedJobsIterator(ctx, qctx.Queue, sch.schedulingContext.Pool, jobRepo)
queueIt := NewQueuedJobsIterator(ctx, qctx.Queue, sch.schedulingContext.Pool, sch.constraints.GetMaxQueueLookBack(), jobRepo)
jobIteratorByQueue[qctx.Queue] = NewMultiJobsIterator(evictedIt, queueIt)
}
}
Expand Down
29 changes: 3 additions & 26 deletions internal/scheduler/scheduling/queue_scheduler.go
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ func NewQueueScheduler(
}
gangIteratorsByQueue := make(map[string]*QueuedGangIterator)
for queue, it := range jobIteratorByQueue {
gangIteratorsByQueue[queue] = NewQueuedGangIterator(sctx, it, constraints.GetMaxQueueLookBack(), true)
gangIteratorsByQueue[queue] = NewQueuedGangIterator(sctx, it, true)
}
candidateGangIterator, err := NewCandidateGangIterator(sctx.Pool, sctx, sctx.FairnessCostProvider, gangIteratorsByQueue, considerPriorityClassPriority)
if err != nil {
Expand Down Expand Up @@ -220,20 +220,15 @@ type QueuedGangIterator struct {
queuedJobsIterator JobContextIterator
// Groups jctxs by the gang they belong to.
jctxsByGangId map[string][]*schedulercontext.JobSchedulingContext
// Maximum number of jobs to look at before giving up.
maxLookback uint
// If true, do not yield jobs known to be unschedulable.
skipKnownUnschedulableJobs bool
// Number of jobs we have seen so far.
jobsSeen uint
next *schedulercontext.GangSchedulingContext
next *schedulercontext.GangSchedulingContext
}

func NewQueuedGangIterator(sctx *schedulercontext.SchedulingContext, it JobContextIterator, maxLookback uint, skipKnownUnschedulableJobs bool) *QueuedGangIterator {
func NewQueuedGangIterator(sctx *schedulercontext.SchedulingContext, it JobContextIterator, skipKnownUnschedulableJobs bool) *QueuedGangIterator {
return &QueuedGangIterator{
schedulingContext: sctx,
queuedJobsIterator: it,
maxLookback: maxLookback,
skipKnownUnschedulableJobs: skipKnownUnschedulableJobs,
jctxsByGangId: make(map[string][]*schedulercontext.JobSchedulingContext),
}
Expand All @@ -256,9 +251,6 @@ func (it *QueuedGangIterator) Clear() error {
}

func (it *QueuedGangIterator) Peek() (*schedulercontext.GangSchedulingContext, error) {
if it.hitLookbackLimit() {
return nil, nil
}
if it.next != nil {
return it.next, nil
}
Expand All @@ -274,14 +266,6 @@ func (it *QueuedGangIterator) Peek() (*schedulercontext.GangSchedulingContext, e
return nil, nil
}

// Queue lookback limits. Rescheduled jobs don't count towards the limit.
if !jctx.IsEvicted {
it.jobsSeen++
}
if it.hitLookbackLimit() {
return nil, nil
}

// Skip this job if it's known to be unschedulable.
if it.skipKnownUnschedulableJobs && len(it.schedulingContext.UnfeasibleSchedulingKeys) > 0 {
schedulingKey, ok := jctx.SchedulingKey()
Expand Down Expand Up @@ -317,13 +301,6 @@ func (it *QueuedGangIterator) Peek() (*schedulercontext.GangSchedulingContext, e
}
}

func (it *QueuedGangIterator) hitLookbackLimit() bool {
if it.maxLookback == 0 {
return false
}
return it.jobsSeen > it.maxLookback
}

// CandidateGangIterator determines which gang to try scheduling next across queues.
// Specifically, it yields the next gang in the queue with smallest fraction of its fair share,
// where the fraction of fair share computation includes the yielded gang.
Expand Down
12 changes: 0 additions & 12 deletions internal/scheduler/scheduling/queue_scheduler_test.go
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Expand Up @@ -358,18 +358,6 @@ func TestQueueScheduler(t *testing.T) {
Queues: testfixtures.SingleQueuePriorityOne("A"),
ExpectedScheduledIndices: []int{0},
},
"MaxQueueLookback": {
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@d80tb7 d80tb7 Oct 12, 2024

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This no longer applies

SchedulingConfig: testfixtures.WithMaxQueueLookbackConfig(3, testfixtures.TestSchedulingConfig()),
Nodes: testfixtures.N32CpuNodes(1, testfixtures.TestPriorities),
Jobs: armadaslices.Concatenate(
testfixtures.N1Cpu4GiJobs("A", testfixtures.PriorityClass0, 1),
testfixtures.N32Cpu256GiJobs("A", testfixtures.PriorityClass0, 3),
testfixtures.N1Cpu4GiJobs("A", testfixtures.PriorityClass0, 1),
),
Queues: testfixtures.SingleQueuePriorityOne("A"),
ExpectedScheduledIndices: []int{0},
ExpectedNeverAttemptedIndices: []int{3, 4},
},
"gang success": {
SchedulingConfig: testfixtures.TestSchedulingConfig(),
Nodes: testfixtures.N32CpuNodes(2, testfixtures.TestPriorities),
Expand Down