From b97b24856f611998ade3ac7390074dc02b880b19 Mon Sep 17 00:00:00 2001
From: John Eckersberg <jeckersb@redhat.com>
Date: Wed, 28 Mar 2018 15:01:36 -0400
Subject: [PATCH] Use eventlet-aware threading events

For the gory details behind this, see:

https://bugzilla.redhat.com/show_bug.cgi?id=1384183

In summary, if you use threading.Event on python2 with eventlet, it
unnecessarily spams system calls to epoll_wait and burns a *lot* of
CPU cycles by constantly context-switching.

I added eventletutils.Event to oslo_utils a while back to
intelligently use the eventlet Event object when eventlet is being
used, and to fall back to the threading one otherwise.  So just use
that and it will do the right thing.

Depends-On: https://review.openstack.org/#/c/558879/
Change-Id: I6ca0d0fc2a2ff393bab502a5f705fb0d63c32c6b
---
 lower-constraints.txt               | 2 +-
 mistral/rpc/kombu/kombu_listener.py | 3 ++-
 mistral/rpc/kombu/kombu_server.py   | 5 +++--
 requirements.txt                    | 2 +-
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/lower-constraints.txt b/lower-constraints.txt
index 8cda2555e..394729ad4 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -80,7 +80,7 @@ oslo.middleware==3.31.0
 oslo.policy==1.30.0
 oslo.serialization==2.18.0
 oslo.service==1.24.0
-oslo.utils==3.33.0
+oslo.utils==3.37.0
 oslosphinx==4.7.0
 oslotest==3.2.0
 osprofiler==1.4.0
diff --git a/mistral/rpc/kombu/kombu_listener.py b/mistral/rpc/kombu/kombu_listener.py
index 157c0cd2d..d44aa4537 100644
--- a/mistral/rpc/kombu/kombu_listener.py
+++ b/mistral/rpc/kombu/kombu_listener.py
@@ -19,6 +19,7 @@ import six
 import threading
 
 from oslo_log import log as logging
+from oslo_utils import eventletutils
 
 from mistral.rpc.kombu import base as kombu_base
 
@@ -34,7 +35,7 @@ class KombuRPCListener(ConsumerMixin):
         self._thread = None
         self.connection = six.next(self._connections)
 
-        self.ready = threading.Event()
+        self.ready = eventletutils.Event()
 
     def add_listener(self, correlation_id):
         self._results[correlation_id] = six.moves.queue.Queue()
diff --git a/mistral/rpc/kombu/kombu_server.py b/mistral/rpc/kombu/kombu_server.py
index 51c556d02..3ac474255 100644
--- a/mistral/rpc/kombu/kombu_server.py
+++ b/mistral/rpc/kombu/kombu_server.py
@@ -20,6 +20,7 @@ import time
 import kombu
 from oslo_config import cfg
 from oslo_log import log as logging
+from oslo_utils import eventletutils
 from stevedore import driver
 
 from mistral import context as auth_ctx
@@ -68,8 +69,8 @@ class KombuRPCServer(rpc_base.RPCServer, kombu_base.Base):
         self.routing_key = self.topic
         self.channel = None
         self.conn = None
-        self._running = threading.Event()
-        self._stopped = threading.Event()
+        self._running = eventletutils.Event()
+        self._stopped = eventletutils.Event()
         self.endpoints = []
         self._worker = None
         self._thread = None
diff --git a/requirements.txt b/requirements.txt
index f9a7d8455..de9ffb3d5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -24,7 +24,7 @@ oslo.i18n>=3.15.3 # Apache-2.0
 oslo.messaging>=5.29.0 # Apache-2.0
 oslo.middleware>=3.31.0 # Apache-2.0
 oslo.policy>=1.30.0 # Apache-2.0
-oslo.utils>=3.33.0 # Apache-2.0
+oslo.utils>=3.37.0 # Apache-2.0
 oslo.log>=3.36.0 # Apache-2.0
 oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
 oslo.service!=1.28.1,>=1.24.0 # Apache-2.0