diff --git a/Tools/autotest/bisect-helper.py b/Tools/autotest/bisect-helper.py
index 27b974a044..e715dd577a 100755
--- a/Tools/autotest/bisect-helper.py
+++ b/Tools/autotest/bisect-helper.py
@@ -115,7 +115,6 @@ class Bisect(object):
         '''run cmd_list, spewing and setting output in self'''
         self.progress("Running (%s)" % " ".join(cmd_list))
         p = subprocess.Popen(cmd_list,
-                             bufsize=1,
                              stdin=None,
                              close_fds=True,
                              stdout=subprocess.PIPE,
diff --git a/Tools/autotest/check_autotest_speedup.py b/Tools/autotest/check_autotest_speedup.py
index a601dcc5e9..81bf13edfe 100755
--- a/Tools/autotest/check_autotest_speedup.py
+++ b/Tools/autotest/check_autotest_speedup.py
@@ -38,7 +38,6 @@ class CheckAutoTestSpeedup(object):
         '''run cmd_list, spewing and setting output in self'''
         self.progress("Running (%s)" % " ".join(cmd_list))
         p = subprocess.Popen(cmd_list,
-                             bufsize=1,
                              stdin=None,
                              close_fds=True,
                              stdout=subprocess.PIPE,
diff --git a/Tools/scripts/build_binaries.py b/Tools/scripts/build_binaries.py
index f8c0c782ab..074f138ca8 100755
--- a/Tools/scripts/build_binaries.py
+++ b/Tools/scripts/build_binaries.py
@@ -113,7 +113,7 @@ class build_binaries(object):
     def run_program(self, prefix, cmd_list, show_output=True, env=None, force_success=False):
         if show_output:
             self.progress("Running (%s)" % " ".join(cmd_list))
-        p = subprocess.Popen(cmd_list, bufsize=1, stdin=None,
+        p = subprocess.Popen(cmd_list, stdin=None,
                              stdout=subprocess.PIPE, close_fds=True,
                              stderr=subprocess.STDOUT, env=env)
         output = ""