Make recording latency statistics optional.

fuse/fuse.go

@@ -71,6 +71,7 @@ type MountState struct {
 	// For efficient reads and writes.
 	buffers *BufferPool
 
+	RecordStatistics bool
 	statisticsMutex sync.Mutex
 	operationCounts map[string]int64
 
@@ -186,6 +187,7 @@ func (me *MountState) discardRequest(req *request) {
 	endNs := time.Nanoseconds()
 	dt := endNs - req.startNs
 
+	if me.RecordStatistics {
 		me.statisticsMutex.Lock()
 		defer me.statisticsMutex.Unlock()
 
@@ -201,6 +203,7 @@ func (me *MountState) discardRequest(req *request) {
 		key = opname + "-write"
 		me.operationLatencies[key] += (endNs - req.preWriteNs)
 		me.operationCounts[key] += 1
+	}
 
 	me.buffers.FreeBuffer(req.inputBuf)
 	me.buffers.FreeBuffer(req.flatData)