diff --git a/lib/streamaggr/streamaggr.go b/lib/streamaggr/streamaggr.go
index c8de18c304..5fcf4be7e7 100644
--- a/lib/streamaggr/streamaggr.go
+++ b/lib/streamaggr/streamaggr.go
@@ -356,7 +356,7 @@ func (a *aggregator) runFlusher(interval time.Duration) {
 	}
 }
 
-var flushConcurrencyCh = make(chan struct{}, 2*cgroup.AvailableCPUs())
+var flushConcurrencyCh = make(chan struct{}, cgroup.AvailableCPUs())
 
 func (a *aggregator) flush() {
 	ctx := &flushCtx{