diff --git a/pkg/remote/trans/nphttp2/grpc/controlbuf.go b/pkg/remote/trans/nphttp2/grpc/controlbuf.go
index 7e3f8bce45..20996c0935 100644
--- a/pkg/remote/trans/nphttp2/grpc/controlbuf.go
+++ b/pkg/remote/trans/nphttp2/grpc/controlbuf.go
@@ -830,10 +830,12 @@ func (l *loopyWriter) applySettings(ss []http2.Setting) error {
 // to be sent and stream has some stream-level flow control.
 func (l *loopyWriter) processData() (bool, error) {
 	if l.sendQuota == 0 {
+		klog.Infof("connection quota is 0, connection quota: %d, stream window: %d", l.sendQuota, l.oiws)
 		return true, nil
 	}
 	str := l.activeStreams.dequeue() // Remove the first stream.
 	if str == nil {
+		klog.Infof("stream is nil, connection quota: %d, stream window: %d", l.sendQuota, l.oiws)
 		return true, nil
 	}
 	dataItem := str.itl.peek().(*dataFrame) // Peek at the first data item this stream.
@@ -868,6 +870,7 @@ func (l *loopyWriter) processData() (bool, error) {
 	maxSize := http2MaxFrameLen
 	if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota <= 0 { // stream-level flow control.
 		str.state = waitingOnStreamQuota
+		klog.CtxInfof(str.wq.ctx, "stream flow control, connection quota: %d, stream window: %d, bytesOutstanding: %d", l.sendQuota, l.oiws, str.bytesOutStanding)
 		return false, nil
 	} else if maxSize > strQuota {
 		maxSize = strQuota
@@ -896,7 +899,9 @@ func (l *loopyWriter) processData() (bool, error) {
 	size := hSize + dSize
 
 	// Now that outgoing flow controls are checked we can replenish str's write quota
-	str.wq.replenish(size)
+	if stillBlock := str.wq.replenish(size); stillBlock {
+		klog.CtxInfof(str.wq.ctx, "stream still blocked, connection quota: %d, stream window: %d, bytesOutstanding: %d", l.sendQuota, l.oiws, str.bytesOutStanding)
+	}
 	var endStream bool
 	// If this is the last data message on this stream and all of it can be written in this iteration.
 	if dataItem.endStream && len(dataItem.h)+len(dataItem.d) <= size {
@@ -929,6 +934,7 @@ func (l *loopyWriter) processData() (bool, error) {
 			return false, err
 		}
 	} else if int(l.oiws)-str.bytesOutStanding <= 0 { // Ran out of stream quota.
+		klog.CtxInfof(str.wq.ctx, "ran out ot stream quota, connection quota: %d, stream window: %d, bytesOutstanding: %d", l.sendQuota, l.oiws, str.bytesOutStanding)
 		str.state = waitingOnStreamQuota
 	} else { // Otherwise add it back to the list of active streams.
 		l.activeStreams.enqueue(str)
diff --git a/pkg/remote/trans/nphttp2/grpc/flowcontrol.go b/pkg/remote/trans/nphttp2/grpc/flowcontrol.go
index d3833d88e3..ec98206cb8 100644
--- a/pkg/remote/trans/nphttp2/grpc/flowcontrol.go
+++ b/pkg/remote/trans/nphttp2/grpc/flowcontrol.go
@@ -93,7 +93,7 @@ type ctxWriteQuota struct {
 	// replenish is called by loopyWriter to give quota back to.
 	// It is implemented as a field so that it can be updated
 	// by tests.
-	replenish func(n int)
+	replenish func(n int) bool
 }
 
 func newCtxWriteQuota(ctx context.Context, sz int32, done <-chan struct{}) *ctxWriteQuota {
@@ -124,17 +124,23 @@ func (w *ctxWriteQuota) get(sz int32) error {
 	}
 }
 
-func (w *ctxWriteQuota) realReplenish(n int) {
+func (w *ctxWriteQuota) realReplenish(n int) bool {
 	sz := int32(n)
 	a := atomic.AddInt32(&w.quota, sz)
 	b := a - sz
-	if b <= 0 && a > 0 {
-		select {
-		case w.ch <- struct{}{}:
-			klog.CtxInfof(w.ctx, "replenish quota success, curQuota: %d, oriQuota: %d", a, b)
-		default:
+	if b <= 0 {
+		if a > 0 {
+			select {
+			case w.ch <- struct{}{}:
+				klog.CtxInfof(w.ctx, "replenish quota success, curQuota: %d, oriQuota: %d", a, b)
+			default:
+			}
+		} else {
+			klog.CtxInfof(w.ctx, "replenish quota failed, curQuota: %d, oriQuota: %d", a, b)
+			return false
 		}
 	}
+	return true
 }
 
 type trInFlow struct {