diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriterBitmapPreparer.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriterBitmapPreparer.java
index fbd9cbacd..99db74956 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriterBitmapPreparer.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriterBitmapPreparer.java
@@ -452,6 +452,7 @@ class PackWriterBitmapPreparer {
 		RevCommit rc;
 		while ((rc = rw.next()) != null && pos > 0) {
 			commits[--pos] = rc;
+			pm.update(1);
 		}
 
 		// Sort the new wants by reverse commit time.