Index: utils/libcxx/test/format.py
===================================================================
--- utils/libcxx/test/format.py
+++ utils/libcxx/test/format.py
@@ -12,6 +12,7 @@
 import os
 import time
 import random
+import platform
 
 import lit.Test        # pylint: disable=import-error
 import lit.TestRunner  # pylint: disable=import-error
@@ -202,6 +203,12 @@
                           for f in os.listdir(local_cwd) if f.endswith('.dat')]
             is_flaky = self._get_parser('FLAKY_TEST.', parsers).getValue()
             max_retry = 3 if is_flaky else 1
+
+            # LIBC++ tests tend to be more flaky on NetBSD, so add more retries.
+            # We don't do this on other platforms because it's slower.
+            if platform.system() in ['NetBSD']:
+                max_retry = max_retry * 3
+
             for retry_count in range(max_retry):
                 cmd, out, err, rc = self.executor.run(exec_path, [exec_path],
                                                       local_cwd, data_files,