query: support more than 1 job per worker

A worker is now able to be queried more than 1 job at a time with
maxJobs constant introduced to limit the job per peer.

Author: kcalvinalvin

query/worker.go

@@ -2,6 +2,7 @@ package query
 
 import (
 	"errors"
+	"sync/atomic"
 	"time"
 
 	"github.com/btcsuite/btcd/wire"
@@ -58,6 +59,10 @@ type jobResult struct {
 type worker struct {
 	peer Peer
 
+	// quit indicates that the worker has already quit and is not accepting
+	// any more jobs.
+	quit int32
+
 	// nextJob is a channel of queries to be distributed, where the worker
 	// will poll new work from.
 	nextJob chan *queryJob
@@ -70,7 +75,7 @@ var _ Worker = (*worker)(nil)
 func NewWorker(peer Peer) Worker {
 	return &worker{
 		peer:    peer,
-		nextJob: make(chan *queryJob),
+		nextJob: make(chan *queryJob, maxJobs),
 	}
 }
 
@@ -88,7 +93,10 @@ func (w *worker) Run(results chan<- *jobResult, quit <-chan struct{}) {
 
 	// Subscribe to messages from the peer.
 	msgChan, cancel := peer.SubscribeRecvMsg()
-	defer cancel()
+	defer func() {
+		atomic.AddInt32(&w.quit, 1)
+		cancel()
+	}()
 
 	for {
 		log.Tracef("Worker %v waiting for more work", peer.Addr())
@@ -266,5 +274,10 @@ func (w *worker) Run(results chan<- *jobResult, quit <-chan struct{}) {
 //
 // NOTE: Part of the Worker interface.
 func (w *worker) NewJob() chan<- *queryJob {
+	// The worker has already quit so don't return the nextJob channel.
+	if atomic.LoadInt32(&w.quit) != 0 {
+		return nil
+	}
+
 	return w.nextJob
 }

query/worker_test.go

@@ -86,7 +86,7 @@ func makeJob() *queryJob {
 }
 
 type testCtx struct {
-	nextJob    chan<- *queryJob
+	worker     Worker
 	jobResults chan *jobResult
 	peer       *mockPeer
 	workerDone chan struct{}
@@ -101,7 +101,7 @@ func startWorker() (*testCtx, error) {
 		subscriptions: make(chan chan wire.Message),
 		quit:          make(chan struct{}),
 	}
-	results := make(chan *jobResult)
+	results := make(chan *jobResult, maxJobs)
 	quit := make(chan struct{})
 
 	wk := NewWorker(peer)
@@ -123,7 +123,7 @@ func startWorker() (*testCtx, error) {
 	peer.responses = sub
 
 	return &testCtx{
-		nextJob:    wk.NewJob(),
+		worker:     wk,
 		jobResults: results,
 		peer:       peer,
 		workerDone: done,
@@ -144,7 +144,7 @@ func TestWorkerIgnoreMsgs(t *testing.T) {
 	task := makeJob()
 
 	select {
-	case ctx.nextJob <- task:
+	case ctx.worker.NewJob() <- task:
 	case <-time.After(1 * time.Second):
 		t.Fatalf("did not pick up job")
 	}
@@ -215,7 +215,7 @@ func TestWorkerTimeout(t *testing.T) {
 
 	// Give the worker the new job.
 	select {
-	case ctx.nextJob <- task:
+	case ctx.worker.NewJob() <- task:
 	case <-time.After(1 * time.Second):
 		t.Fatalf("did not pick up job")
 	}
@@ -253,7 +253,7 @@ func TestWorkerTimeout(t *testing.T) {
 
 	// It will immediately attempt to fetch another task.
 	select {
-	case ctx.nextJob <- task:
+	case ctx.worker.NewJob() <- task:
 	case <-time.After(1 * time.Second):
 		t.Fatalf("did not pick up job")
 	}
@@ -272,7 +272,7 @@ func TestWorkerDisconnect(t *testing.T) {
 	// Give the worker a new job.
 	task := makeJob()
 	select {
-	case ctx.nextJob <- task:
+	case ctx.worker.NewJob() <- task:
 	case <-time.After(1 * time.Second):
 		t.Fatalf("did not pick up job")
 	}
@@ -312,7 +312,7 @@ func TestWorkerDisconnect(t *testing.T) {
 
 	// No more jobs should be accepted by the worker after it has exited.
 	select {
-	case ctx.nextJob <- task:
+	case ctx.worker.NewJob() <- task:
 		t.Fatalf("exited worker did pick up job")
 	default:
 	}
@@ -342,7 +342,7 @@ func TestWorkerProgress(t *testing.T) {
 	task.timeout = taskTimeout
 
 	select {
-	case ctx.nextJob <- task:
+	case ctx.worker.NewJob() <- task:
 	case <-time.After(1 * time.Second):
 		t.Fatalf("did not pick up job")
 	}
@@ -421,7 +421,7 @@ func TestWorkerJobCanceled(t *testing.T) {
 	canceled := false
 	for i := 0; i < 2; i++ {
 		select {
-		case ctx.nextJob <- task:
+		case ctx.worker.NewJob() <- task:
 		case <-time.After(1 * time.Second):
 			t.Fatalf("did not pick up job")
 		}

query/workmanager.go

@@ -15,6 +15,9 @@ const (
 
 	// maxQueryTimeout is the maximum timeout given to a single query.
 	maxQueryTimeout = 32 * time.Second
+
+	// maxJobs is the maximum amount of jobs a single worker can have.
+	maxJobs = 32
 )
 
 var (
@@ -74,7 +77,6 @@ type PeerRanking interface {
 
 // activeWorker wraps a Worker that is currently running, together with the job
 // we have given to it.
-// TODO(halseth): support more than one active job at a time.
 type activeWorker struct {
 	w          Worker
 	activeJobs map[uint64]*queryJob
@@ -202,8 +204,10 @@ func (w *peerWorkManager) handleJobResult(result *jobResult) {
 
 	// Delete the job from the worker's active job, such
 	// that the slot gets opened for more work.
-	r := w.workers[result.peer.Addr()]
-	delete(r.activeJobs, result.job.Index())
+	r, found := w.workers[result.peer.Addr()]
+	if found {
+		delete(r.activeJobs, result.job.Index())
+	}
 
 	// Get the index of this query's batch, and delete it
 	// from the map of current queries, since we don't have
@@ -438,7 +442,7 @@ Loop:
 			for p, r := range w.workers {
 				// Only one active job at a time is currently
 				// supported.
-				if len(r.activeJobs) >= 1 {
+				if len(r.activeJobs) >= maxJobs {
 					continue
 				}
 

query/workmanager_test.go

@@ -84,8 +84,8 @@ func startWorkManager(t *testing.T, numWorkers int) (WorkManager,
 		NewWorker: func(peer Peer) Worker {
 			m := &mockWorker{
 				peer:    peer,
-				nextJob: make(chan *queryJob),
-				results: make(chan *jobResult),
+				nextJob: make(chan *queryJob, maxJobs),
+				results: make(chan *jobResult, maxJobs),
 			}
 			workerChan <- m
 			return m
@@ -205,7 +205,7 @@ func TestWorkManagerWorkDispatcherFailures(t *testing.T) {
 	for i := 0; i < numQueries; i++ {
 		q := &Request{}
 		queries[i] = q
-		scheduledJobs[i] = make(chan sched)
+		scheduledJobs[i] = make(chan sched, maxJobs)
 	}
 
 	// For each worker, spin up a goroutine that will forward the job it
@@ -387,7 +387,7 @@ func TestWorkManagerCancelBatch(t *testing.T) {
 // TestWorkManagerWorkRankingScheduling checks that the work manager schedules
 // jobs among workers according to the peer ranking.
 func TestWorkManagerWorkRankingScheduling(t *testing.T) {
-	const numQueries = 4
+	const numQueries = 4 * maxJobs
 	const numWorkers = 8
 
 	workMgr, workers := startWorkManager(t, numWorkers)
@@ -414,7 +414,7 @@ func TestWorkManagerWorkRankingScheduling(t *testing.T) {
 	var jobs []*queryJob
 	for i := 0; i < numQueries; i++ {
 		select {
-		case job := <-workers[i].nextJob:
+		case job := <-workers[i/maxJobs].nextJob:
 			if job.index != uint64(i) {
 				t.Fatalf("unexpected job")
 			}
@@ -449,7 +449,7 @@ func TestWorkManagerWorkRankingScheduling(t *testing.T) {
 	// Go backwards, and succeed the queries.
 	for i := numQueries - 1; i >= 0; i-- {
 		select {
-		case workers[i].results <- &jobResult{
+		case workers[i/maxJobs].results <- &jobResult{
 			job: jobs[i],
 			err: nil,
 		}: