Merge "FUP: Translate scatter-gather to futurist"

nova/conf/base.py

@@ -75,7 +75,8 @@ greenthread pool concurrently, defaults to 1000, min value is 100.
         help='''
 The number of tasks that can run concurrently, one for each cell, for
 operations requires cross cell data gathering a.k.a scatter-gather, like
-listing instances across multiple cells.
+listing instances across multiple cells. This is only used if the service is
+running in native thread mode.
 '''),
 ]
 

nova/tests/unit/test_context.py

@@ -389,6 +389,8 @@ class ContextTestCase(test.NoDBTestCase):
                                        uuid=uuids.cell1)
         mappings = objects.CellMappingList(objects=[mapping0, mapping1])
 
+        # We call scatter gather with a short (1s) timeout, dispatching two
+        # tasks where the second will wait forever on our work semaphore above.
         results = context.scatter_gather_cells(ctxt, mappings, 1, task)
         self.assertEqual(2, len(results))
         self.assertEqual(
@@ -427,6 +429,8 @@ class ContextTestCase(test.NoDBTestCase):
                                        uuid=uuids.cell1)
         mappings = objects.CellMappingList(objects=[mapping0, mapping1])
 
+        # We call scatter gather with a short (1s) timeout, dispatching two
+        # tasks that will wait forever on our work event above.
         results = context.scatter_gather_cells(
             ctxt, mappings, 1, task)