hscontrol/state: make NodeStore batch configuration tunable (#2886)

hscontrol/state/node_store.go

@@ -14,11 +14,6 @@ import (
 	"tailscale.com/types/views"
 )
 
-const (
-	batchSize    = 100
-	batchTimeout = 500 * time.Millisecond
-)
-
 const (
 	put             = 1
 	del             = 2
@@ -92,9 +87,12 @@ type NodeStore struct {
 
 	peersFunc  PeersFunc
 	writeQueue chan work
+
+	batchSize    int
+	batchTimeout time.Duration
 }
 
-func NewNodeStore(allNodes types.Nodes, peersFunc PeersFunc) *NodeStore {
+func NewNodeStore(allNodes types.Nodes, peersFunc PeersFunc, batchSize int, batchTimeout time.Duration) *NodeStore {
 	nodes := make(map[types.NodeID]types.Node, len(allNodes))
 	for _, n := range allNodes {
 		nodes[n.ID] = *n
@@ -102,7 +100,9 @@ func NewNodeStore(allNodes types.Nodes, peersFunc PeersFunc) *NodeStore {
 	snap := snapshotFromNodes(nodes, peersFunc)
 
 	store := &NodeStore{
-		peersFunc: peersFunc,
+		peersFunc:    peersFunc,
+		batchSize:    batchSize,
+		batchTimeout: batchTimeout,
 	}
 	store.data.Store(&snap)
 
@@ -249,9 +249,10 @@ func (s *NodeStore) Stop() {
 
 // processWrite processes the write queue in batches.
 func (s *NodeStore) processWrite() {
-	c := time.NewTicker(batchTimeout)
+	c := time.NewTicker(s.batchTimeout)
 	defer c.Stop()
-	batch := make([]work, 0, batchSize)
+
+	batch := make([]work, 0, s.batchSize)
 
 	for {
 		select {
@@ -264,17 +265,19 @@ func (s *NodeStore) processWrite() {
 				return
 			}
 			batch = append(batch, w)
-			if len(batch) >= batchSize {
+			if len(batch) >= s.batchSize {
 				s.applyBatch(batch)
 				batch = batch[:0]
-				c.Reset(batchTimeout)
+
+				c.Reset(s.batchTimeout)
 			}
 		case <-c.C:
 			if len(batch) != 0 {
 				s.applyBatch(batch)
 				batch = batch[:0]
 			}
-			c.Reset(batchTimeout)
+
+			c.Reset(s.batchTimeout)
 		}
 	}
 }