When using eventlet monkey_patch()'d code, greenthreads can be
blocked on connection for several seconds while the database
contents are parsed. Eventlet recommends adding a sleep(0) call
to cooperatively yield in cpu-bound code. asyncio code has
asyncio.sleep(0). This patch adds an API method that defaults to
doing nothing, but can be overridden to yield as needed.
Signed-off-by: Terry Wilson <twil...@redhat.com>
---
python/ovs/db/idl.py | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/python/ovs/db/idl.py b/python/ovs/db/idl.py
index 889cf3431..751feb47f 100644
--- a/python/ovs/db/idl.py
+++ b/python/ovs/db/idl.py
@@ -479,6 +479,15 @@ class Idl(object):
:type updates: Row
"""
+ def cooperative_yield(self):
+ """Hook for cooperatively yielding to eventlet/gevent/asyncio/etc.
+
+ When a block of code is going to spend a lot of time cpu-bound without
+ doing any I/O, it can cause greenthread/coroutine libraries to block.
+ This call should be added to code where this can happen, but defaults
+ to doing nothing to avoid overhead where it is not needed.
+ """
+
def __send_cond_change(self, table, cond):
monitor_cond_change = {table.name: [{"where": cond}]}
old_uuid = str(self.uuid)
@@ -644,6 +653,8 @@ class Idl(object):
'is not an object'
% (table_name, uuid_string))
+ self.cooperative_yield()
+
if version == OVSDB_UPDATE2:
changes = self.__process_update2(table, uuid, row_update)
if changes:
--
2.17.1
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