openstack
/
glance
Code Issues Proposed changes

Limit default workers to 8 

With modern servers it's not uncommon to see environments that has
dozens of logical processors. Glance defaults workers to number of
these logical processors seen by OS and each worker spins up pool
of 1000 threads. Having dozens of these thread pools consuming
resources is total overkill for most of the environments.

This change limits the amount of workers used by default to 8 which
should be plenty for most of the deployments. This limitation does
not affect if more workers is specifically configured in the config
file.

Change-Id: I6fcf2f8a416e34c0c719e1abd73f0525e686be5e
Closes-Bug: #1748916
This commit is contained in:
Erno Kuvaja 2018-02-12 16:58:03 +00:00
parent 0b6e007235
commit 6f87c7d567
2 changed files with 28 additions and 5 deletions
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11
glance/common/wsgi.py
View File

@ -207,7 +207,10 @@ Number of Glance worker processes to start.
Provide a non-negative integer value to set the number of child
process workers to service requests. By default, the number of CPUs
available is set as the value for ``workers``.
available is set as the value for ``workers`` limited to 8. For
example if the processor count is 6, 6 workers will be used, if the
processor count is 24 only 8 workers will be used. The limit will only
apply to the default value, if 24 workers is configured, 24 is used.
Each worker process is made to listen on the port set in the
configuration file and contains a greenthread pool of size 1000.
@ -332,8 +335,10 @@ except ImportError:
def get_num_workers():
"""Return the configured number of workers."""
if CONF.workers is None:
# None implies the number of CPUs
return processutils.get_worker_count()
# None implies the number of CPUs limited to 8
# See Launchpad bug #1748916 and the config help text
workers = processutils.get_worker_count()
return workers if workers < 8 else 8
return CONF.workers

22
glance/tests/unit/common/test_wsgi.py
View File

@ -604,7 +604,7 @@ class ServerTest(test_utils.BaseTestCase):
socket_timeout=900)
def test_number_of_workers(self):
"""Ensure the default number of workers matches num cpus."""
"""Ensure the number of workers matches num cpus limited to 8."""
def pid():
i = 1
while True:
@ -612,12 +612,30 @@ class ServerTest(test_utils.BaseTestCase):
yield i
with mock.patch.object(os, 'fork') as mock_fork:
with mock.patch('oslo_concurrency.processutils.get_worker_count',
return_value=4):
mock_fork.side_effect = pid
server = wsgi.Server()
server.configure = mock.Mock()
fake_application = "fake-application"
server.start(fake_application, None)
self.assertEqual(4, len(server.children))
with mock.patch('oslo_concurrency.processutils.get_worker_count',
return_value=24):
mock_fork.side_effect = pid
server = wsgi.Server()
server.configure = mock.Mock()
fake_application = "fake-application"
server.start(fake_application, None)
self.assertEqual(8, len(server.children))
mock_fork.side_effect = pid
server = wsgi.Server()
server.configure = mock.Mock()
fake_application = "fake-application"
server.start(fake_application, None)
self.assertEqual(processutils.get_worker_count(),
cpus = processutils.get_worker_count()
expected_workers = cpus if cpus < 8 else 8
self.assertEqual(expected_workers,
len(server.children))