diff --git a/include/silk/fibers/blocking-queue.h b/include/silk/fibers/blocking-queue.h
index d52cad3..2d36fce 100644
--- a/include/silk/fibers/blocking-queue.h
+++ b/include/silk/fibers/blocking-queue.h
@@ -113,8 +113,12 @@ class FiberBlockingQueue
 
 private:
     BoundedQueue<T> queue;
-    FiberFutex spaceAvailable;
-    FiberFutex itemAvailable;
+
+    /** Posted by dequeue, read by every enqueue; cache-line isolated from dequeuePos and itemAvailable. */
+    alignas(kCacheLineSize) FiberFutex spaceAvailable;
+
+    /** Posted by every enqueue, waited by dequeue; isolated so producer posts never invalidate the consumer's lines. */
+    alignas(kCacheLineSize) FiberFutex itemAvailable;
 };
 
 } // namespace silk