[Python-checkins] cpython (3.6): Issue #26939: Add the support.setswitchinterval() function to fix

[xavier.degaye]

https://hg.python.org/cpython/rev/fd1718badb67
changeset:   105522:fd1718badb67
branch:      3.6
parent:      105520:4745d801cae2
user:        Xavier de Gaye <xdegaye at users.sourceforge.net>
date:        Thu Dec 08 11:06:56 2016 +0100
summary:
  Issue #26939: Add the support.setswitchinterval() function to fix
test_functools hanging on the Android armv7 qemu emulator.

files:
  Lib/test/support/__init__.py |  16 ++++++++++++++++
  Lib/test/test_functools.py   |   2 +-
  Misc/NEWS                    |   6 ++++++
  3 files changed, 23 insertions(+), 1 deletions(-)


diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -93,6 +93,7 @@
     "check__all__", "requires_android_level", "requires_multiprocessing_queue",
     # sys
     "is_jython", "is_android", "check_impl_detail", "unix_shell",
+    "setswitchinterval",
     # network
     "HOST", "IPV6_ENABLED", "find_unused_port", "bind_port", "open_urlresource",
     # processes
@@ -2547,3 +2548,18 @@
             continue
         if spawn.find_executable(cmd[0]) is None:
             return cmd[0]
+
+
+_is_android_emulator = None
+def setswitchinterval(interval):
+    # Setting a very low gil interval on the Android emulator causes python
+    # to hang (issue #26939).
+    minimum_interval = 1e-5
+    if is_android and interval < minimum_interval:
+        global _is_android_emulator
+        if _is_android_emulator is None:
+            _is_android_emulator = (subprocess.check_output(
+                               ['getprop', 'ro.kernel.qemu']).strip() == b'1')
+        if _is_android_emulator:
+            interval = minimum_interval
+    return sys.setswitchinterval(interval)
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -1322,7 +1322,7 @@
                 f.cache_clear()
 
         orig_si = sys.getswitchinterval()
-        sys.setswitchinterval(1e-6)
+        support.setswitchinterval(1e-6)
         try:
             # create n threads in order to fill cache
             threads = [threading.Thread(target=full, args=[k])
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -22,6 +22,12 @@
 - Issue #28847: dbm.dumb now supports reading read-only files and no longer
   writes the index file when it is not changed.
 
+Tests
+-----
+
+- Issue #26939: Add the support.setswitchinterval() function to fix
+  test_functools hanging on the Android armv7 qemu emulator.
+
 
 What's New in Python 3.6.0 release candidate 1
 ==============================================

-- 
Repository URL: https://hg.python.org/cpython