From 0eea513a901cdda275dffdbd592b2f1492ecd98d Mon Sep 17 00:00:00 2001
From: James Cherry <cherry@parallaxsw.com>
Date: Tue, 15 Sep 2020 20:18:13 -0700
Subject: [PATCH] PathGroups::makeGroupPathEnds only use dispatch queue when
 threads>1

---
 search/PathGroup.cc | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/search/PathGroup.cc b/search/PathGroup.cc
index 0afe3ab2..cfa8e9bc 100644
--- a/search/PathGroup.cc
+++ b/search/PathGroup.cc
@@ -897,15 +897,22 @@ PathGroups::makeGroupPathEnds(VertexSet *endpoints,
 			      const MinMaxAll *min_max,
 			      PathEndVisitor *visitor)
 {
-  Vector<MakeEndpointPathEnds*> visitors;
-  for (int i = 0; i < thread_count_; i++)
-    visitors.push_back(new MakeEndpointPathEnds(visitor, corner, min_max, this));
-  for (auto endpoint : *endpoints) {
-    dispatch_queue_->dispatch( [endpoint, &visitors](int i)
-			       { visitors[i]->visit(endpoint); } );
+  if (thread_count_ == 1) {
+    MakeEndpointPathEnds end_visitor(visitor, corner, min_max, this);
+    for (auto endpoint : *endpoints)
+      end_visitor.visit(endpoint);
+  }
+  else {
+    Vector<MakeEndpointPathEnds*> visitors;
+    for (int i = 0; i < thread_count_; i++)
+      visitors.push_back(new MakeEndpointPathEnds(visitor, corner, min_max, this));
+    for (auto endpoint : *endpoints) {
+      dispatch_queue_->dispatch( [endpoint, &visitors](int i)
+				 { visitors[i]->visit(endpoint); } );
+    }
+    dispatch_queue_->finishTasks();
+    visitors.deleteContents();
   }
-  dispatch_queue_->finishTasks();
-  visitors.deleteContents();
 }
 
 } // namespace