18 lines
720 B
ReStructuredText
18 lines
720 B
ReStructuredText
Threading model
|
|
===============
|
|
|
|
All OpenStack services use *green thread* model of threading, implemented
|
|
through using the Python `eventlet <http://eventlet.net/>`_ and
|
|
`greenlet <http://packages.python.org/greenlet/>`_ libraries.
|
|
|
|
Green threads use a cooperative model of threading: thread context
|
|
switches can only occur when specific eventlet or greenlet library calls are
|
|
made (e.g., sleep, certain I/O calls). From the operating system's point of
|
|
view, each OpenStack service runs in a single thread.
|
|
|
|
The use of green threads reduces the likelihood of race conditions, but does
|
|
not completely eliminate them. In some cases, you may need to use the
|
|
``@utils.synchronized(...)`` decorator to avoid races.
|
|
|
|
|