diff --git a/oviewer/control_test.go b/oviewer/control_test.go
index 04edade..1d87d92 100644
--- a/oviewer/control_test.go
+++ b/oviewer/control_test.go
@@ -161,9 +161,7 @@ func TestDocument_requestLoad(t *testing.T) {
 			if err := m.ControlFile(f); err != nil {
 				t.Fatalf("Document.ControlFile() fatal = %v, wantErr %v", err, tt.wantErr)
 			}
-			for !m.BufEOF() {
-			}
-
+			m.WaitEOF()
 			m.requestLoad(tt.fields.chunkNum)
 
 			sc := controlSpecifier{
@@ -235,8 +233,7 @@ func TestDocument_requestSearch(t *testing.T) {
 			if err := m.ControlFile(f); (err != nil) != tt.wantErr {
 				t.Errorf("Document.ControlFile() error = %v, wantErr %v", err, tt.wantErr)
 			}
-			for !m.BufEOF() {
-			}
+			m.WaitEOF()
 			if got := m.requestSearch(tt.fields.chunkNum, searcher); got != tt.want {
 				t.Errorf("Document.requestSearch() = %v, want %v", got, tt.want)
 			}
@@ -304,10 +301,7 @@ func TestDocument_requestFollow(t *testing.T) {
 			if err := m.ControlFile(f); err != nil {
 				t.Fatalf("Document.ControlFile() fatal = %v, wantErr %v", err, tt.wantErr)
 			}
-
-			for !m.BufEOF() {
-			}
-
+			m.WaitEOF()
 			af, err := os.OpenFile(fname, os.O_APPEND|os.O_RDWR, 0o600)
 			if err != nil {
 				t.Fatal("open error", tt.fields.FileName)
@@ -371,8 +365,7 @@ func TestDocument_requestClose(t *testing.T) {
 			if err := m.ControlFile(f); (err != nil) != tt.wantErr {
 				t.Errorf("Document.ControlFile() error = %v, wantErr %v", err, tt.wantErr)
 			}
-			for !m.BufEOF() {
-			}
+			m.WaitEOF()
 			if got := m.requestClose(); got != tt.want {
 				t.Errorf("Document.requestSearch() = %v, want %v", got, tt.want)
 			}
diff --git a/oviewer/document.go b/oviewer/document.go
index e13640c..be29f6c 100644
--- a/oviewer/document.go
+++ b/oviewer/document.go
@@ -59,6 +59,8 @@ type Document struct {
 	// alignConv is an interface that converts alignment.
 	alignConv *align
 
+	cond *sync.Cond
+
 	// fileName is the file name to display.
 	FileName string
 	// Caption is an additional caption to display after the file name.
@@ -232,6 +234,8 @@ func NewDocument() (*Document, error) {
 	}
 	m.alignConv = newAlignConverter(m.ColumnWidth)
 	m.conv = m.converterType(m.general.Converter)
+
+	m.cond = sync.NewCond(&sync.Mutex{})
 	return m, nil
 }
 
@@ -428,6 +432,16 @@ func (m *Document) storeEndNum() int {
 	return int(atomic.LoadInt32(&m.store.endNum))
 }
 
+// WaitEOF waits for EOF.
+func (m *Document) WaitEOF() {
+	m.cond.L.Lock()
+	defer m.cond.L.Unlock()
+	if m.BufEOF() {
+		return
+	}
+	m.cond.Wait()
+}
+
 // BufEOF return true if EOF is reached.
 func (m *Document) BufEOF() bool {
 	return atomic.LoadInt32(&m.store.eof) == 1
diff --git a/oviewer/document_test.go b/oviewer/document_test.go
index a606c59..5cef3fb 100644
--- a/oviewer/document_test.go
+++ b/oviewer/document_test.go
@@ -17,8 +17,7 @@ func docHelper(t *testing.T, str string) *Document {
 	if err := m.ControlReader(bytes.NewBufferString(str), nil); err != nil {
 		t.Fatal(err)
 	}
-	for !m.BufEOF() {
-	}
+	m.WaitEOF()
 	return m
 }
 
@@ -28,9 +27,7 @@ func docFileReadHelper(t *testing.T, fileName string) *Document {
 	if err != nil {
 		t.Fatal(err)
 	}
-	for !m.BufEOF() {
-	}
-
+	m.WaitEOF()
 	return m
 }
 
@@ -162,8 +159,6 @@ func TestDocument_Export(t *testing.T) {
 			t.Parallel()
 			m := docHelper(t, tt.str)
 			w := &bytes.Buffer{}
-			for !m.BufEOF() {
-			}
 			m.bottomLN = m.BufEndNum()
 			if err := m.Export(w, tt.args.start, tt.args.end); err != nil {
 				t.Fatal(err)
diff --git a/oviewer/filter_test.go b/oviewer/filter_test.go
index b73f868..8f724c1 100644
--- a/oviewer/filter_test.go
+++ b/oviewer/filter_test.go
@@ -174,8 +174,9 @@ func TestRoot_filterDocument(t *testing.T) {
 			root.Doc.Header = tt.fields.header
 			root.filterDocument(context.Background(), tt.args.searcher)
 			filterDoc := root.DocList[len(root.DocList)-1]
-			for !filterDoc.BufEOF() {
-			}
+			filterDoc.cond.L.Lock()
+			filterDoc.cond.Wait()
+			filterDoc.cond.L.Unlock()
 			line := filterDoc.getLineC(0)
 			if line.str != tt.want {
 				t.Errorf("filterDocument() = %v, want %v", line.str, tt.want)
@@ -242,8 +243,7 @@ func TestRoot_filterLink(t *testing.T) {
 			ctx := context.Background()
 			root.filterDocument(ctx, tt.args.searcher)
 			filterDoc := root.DocList[len(root.DocList)-1]
-			for !filterDoc.BufEOF() {
-			}
+			filterDoc.WaitEOF()
 			filterDoc.LineNumMode = true
 			root.prepareStartX()
 			filterDoc.topLN = 2
@@ -299,8 +299,7 @@ func TestRoot_closeAllFilter(t *testing.T) {
 			root := rootFileReadHelper(t, tt.fields.fileNames...)
 			root.filterDocument(context.Background(), tt.args.searcher)
 			filterDoc := root.DocList[len(root.DocList)-1]
-			for !filterDoc.BufEOF() {
-			}
+			filterDoc.WaitEOF()
 			ctx := context.Background()
 			root.closeAllFilter(ctx)
 			if len(root.DocList) != tt.want {
diff --git a/oviewer/oviewer_test.go b/oviewer/oviewer_test.go
index b447f22..f25df3c 100644
--- a/oviewer/oviewer_test.go
+++ b/oviewer/oviewer_test.go
@@ -43,8 +43,7 @@ func rootFileReadHelper(t *testing.T, fileNames ...string) *Root {
 	}
 	root.mu.RLock()
 	for _, doc := range root.DocList {
-		for !doc.BufEOF() {
-		}
+		doc.WaitEOF()
 	}
 	root.mu.RUnlock()
 	return root
diff --git a/oviewer/reader.go b/oviewer/reader.go
index ace4646..3c54866 100644
--- a/oviewer/reader.go
+++ b/oviewer/reader.go
@@ -268,6 +268,9 @@ func (m *Document) afterEOF(reader *bufio.Reader) *bufio.Reader {
 		atomic.StoreInt32(&m.tmpLN, atomic.LoadInt32(&m.followStore.endNum))
 		m.cache.Purge()
 	}
+	m.cond.L.Lock()
+	m.cond.Broadcast()
+	m.cond.L.Unlock()
 	if !m.seekable { // for NamedPipe.
 		return bufio.NewReader(m.file)
 	}