Fix poor volume creation performance from glance images

Fixed glance uploads on poor write performing systems: give other
greenthreads a chance to schedule.

Story: 2002893
Task: 22856

Change-Id: I70c192f1c72d8bb1a9f9b7a0fd2545c49c3acb46
Signed-off-by: Jack Ding <jack.ding@windriver.com>

openstack/python-glance-store/centos/meta_patches/0004-meta-Add-glance-schedulre-greenthreads.patch

@@ -0,0 +1,32 @@
+From fc9b9d397b503eeff6585310d8de177b051a11e9 Mon Sep 17 00:00:00 2001
+From: Elena Taivan <elena.taivan@windriver.com>
+Date: Wed, 6 Jun 2018 10:02:56 +0000
+Subject: [PATCH 1/1] meta Add glance schedulre greenthreads
+
+---
+ SPECS/python-glance-store.spec | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/SPECS/python-glance-store.spec b/SPECS/python-glance-store.spec
+index 0c0d728..977b2bc 100644
+--- a/SPECS/python-glance-store.spec
++++ b/SPECS/python-glance-store.spec
+@@ -16,6 +16,7 @@ Source0:        https://tarballs.openstack.org/%{upstream_name}/%{upstream_name}
+ # WRS
+ Patch0001: 0001-Check-ceph-cluster-free-space-before-creating-image.patch
+ Patch0002: 0002-Add-glance-driver.patch
++Patch0003: 0003-Add-glance-schedule-greenthreads.patch
+ 
+ BuildArch:      noarch
+ 
+@@ -90,6 +91,7 @@ Requires:       python3-oslo-privsep >= 1.9.0
+ # Apply WRS patches
+ %patch0001 -p1
+ %patch0002 -p1
++%patch0003 -p1
+ 
+ %build
+ %py2_build
+-- 
+1.8.3.1
+

openstack/python-glance-store/centos/meta_patches/PATCH_ORDER

@@ -1,3 +1,4 @@
 0001-Update-package-versioning-for-TIS-format.patch
 0002-meta-patch-Check-ceph-cluster-free-space.patch
 0003-meta-patch-Glance-Driver.patch
+0004-meta-Add-glance-schedulre-greenthreads.patch

openstack/python-glance-store/centos/patches/0003-Add-glance-schedule-greenthreads.patch

@@ -0,0 +1,33 @@
+From 71f9d9555e0909cbc878d8852cd2c2243abd0b1c Mon Sep 17 00:00:00 2001
+From: Elena Taivan <elena.taivan@windriver.com>
+Date: Wed, 6 Jun 2018 09:41:42 +0000
+Subject: [PATCH 1/1] Add glance schedule greenthreads
+
+---
+ glance_store/_drivers/filesystem.py | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/glance_store/_drivers/filesystem.py b/glance_store/_drivers/filesystem.py
+index 5de011d..4a26d10 100644
+--- a/glance_store/_drivers/filesystem.py
++++ b/glance_store/_drivers/filesystem.py
+@@ -23,6 +23,7 @@ import hashlib
+ import logging
+ import os
+ import stat
++import time
+ 
+ import jsonschema
+ from oslo_config import cfg
+@@ -685,6 +686,8 @@ class Store(glance_store.driver.Store):
+                     if verifier:
+                         verifier.update(buf)
+                     f.write(buf)
++            # Give other greenthreads a chance to schedule.
++            time.sleep(0)
+         except IOError as e:
+             if e.errno != errno.EACCES:
+                 self._delete_partial(filepath, image_id)
+-- 
+1.8.3.1
+