Merge "Make the default executor configurable"

nova/conf/base.py

@@ -62,11 +62,27 @@ entry.
         help='Explicitly specify the temporary working directory.'),
     cfg.IntOpt(
         'default_green_pool_size',
+        deprecated_for_removal=True,
+        deprecated_since='32.0.0',
+        deprecated_reason="""
+This option is only used if the service is running in Eventlet mode. When
+that mode is removed this config option will be removed too.
+""",
         default=1000,
         min=100,
         help='''
 The total number of coroutines that can be run via nova's default
-greenthread pool concurrently, defaults to 1000, min value is 100.
+greenthread pool concurrently, defaults to 1000, min value is 100. It is only
+used if the service is running in Eventlet mode.
+'''),
+    cfg.IntOpt(
+        'default_thread_pool_size',
+        default=10,
+        min=1,
+        help='''
+The total number of threads that can be run via nova's default
+thread pool concurrently. It is only used if the service is running in
+native threading mode.
 '''),
     cfg.IntOpt(
         'cell_worker_thread_pool_size',

nova/test.py

@@ -199,7 +199,7 @@ class TestCase(base.BaseTestCase):
         self._service_fixture_count = collections.defaultdict(int)
 
         self.useFixture(nova_fixtures.OpenStackSDKFixture())
-        self.useFixture(nova_fixtures.IsolatedGreenPoolFixture(self.id()))
+        self.useFixture(nova_fixtures.IsolatedExecutorFixture(self.id()))
 
         self.useFixture(log_fixture.get_logging_handle_error_fixture())
 

nova/tests/fixtures/nova.py

@@ -1185,11 +1185,11 @@ class IndirectionAPIFixture(fixtures.Fixture):
         self.addCleanup(self.cleanup)
 
 
-class IsolatedGreenPoolFixture(fixtures.Fixture):
-    """isolate each test to a dedicated greenpool.
+class IsolatedExecutorFixture(fixtures.Fixture):
+    """isolate each test to a dedicated executor.
 
-    Replace the default shared greenpool with a pre test greenpool
-    and wait for all greenthreads to finish in test cleanup.
+    Replace the default shared executor with a per test executor
+    and wait for all threads to finish in test cleanup.
     """
 
     def __init__(self, test):

nova/tests/unit/test_utils.py

@@ -1500,10 +1500,21 @@ class DefaultExecutorTestCase(test.NoDBTestCase):
 
     @mock.patch.object(
         utils, 'concurrency_mode_threading', new=mock.Mock(return_value=False))
-    def test_executor_type_eventlet(self):
+    def test_executor_type_and_size_eventlet(self):
+        self.flags(default_green_pool_size=113)
         executor = utils._get_default_executor()
 
         self.assertEqual('GreenThreadPoolExecutor', type(executor).__name__)
+        self.assertEqual(113, executor._max_workers)
+
+    @mock.patch.object(
+        utils, 'concurrency_mode_threading', new=mock.Mock(return_value=True))
+    def test_executor_type_and_size_threading(self):
+        self.flags(default_thread_pool_size=13)
+        executor = utils._get_default_executor()
+
+        self.assertEqual('ThreadPoolExecutor', type(executor).__name__)
+        self.assertEqual(13, executor._max_workers)
 
     def test_executor_destroy(self):
         executor = utils._get_default_executor()

nova/utils.py

@@ -111,9 +111,14 @@ def _get_default_executor():
     global DEFAULT_EXECUTOR
 
     if not DEFAULT_EXECUTOR:
-        DEFAULT_EXECUTOR = futurist.GreenThreadPoolExecutor(
-            CONF.default_green_pool_size
-        )
+        if concurrency_mode_threading():
+            DEFAULT_EXECUTOR = futurist.ThreadPoolExecutor(
+                CONF.default_thread_pool_size
+            )
+        else:
+            DEFAULT_EXECUTOR = futurist.GreenThreadPoolExecutor(
+                CONF.default_green_pool_size
+            )
 
         pname = multiprocessing.current_process().name
         executor_name = f"{pname}.default"