Code Profiling¶
As more functionality is added to Neutron over time, efforts to improve performance become more difficult, given the rising complexity of the code. Identifying performance bottlenecks is frequently not straightforward, because they arise as a result of complex interactions of different code components.
To help community developers to improve Neutron performance, a Python decorator has been implemented. Decorating a method or a function with it will result in profiling data being added to the corresponding Neutron component log file. These data are generated using cProfile which is part of the Python standard library.
Once a method or function has been decorated, every one of its executions will add to the corresponding log file data grouped in 3 sections:
The top calls (sorted by CPU cumulative time) made by the decorated method or function. The number of calls included in this section can be controlled by a configuration option, as explained in Setting up Neutron for code profiling. Following is a summary example of this section:
Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: DEBUG neutron.profiling.profiled_decorator [None req-dc2d428f-4531-4f07-a12d-56843b5f9374 c_rally_8af8f2b4_YbhFJ6Ge c_rally_8af8f2b4_fqvy1XJp] os-profiler parent trace-id c5b30c7f-100b-4e1c-8f07-b2c38f41ad65 trace-id 6324fa85-ea5f-4ae2-9d89-2aabff0dddfc 16928 millisecs elapsed for neutron.plugins.ml2.plugin.create_port((<neutron.plugins.ml2.plugin.Ml2Plugin object at 0x7f0b4e6ca978>, <neutron_lib.context.Context object at 0x7f0b4bcee240>, {'port': {'tenant_id': '421ab52e126e45af81a3eb1962613e18', 'network_id': 'dc59577a-9589-4617-82b5-6ee31dbdb15d', 'fixed_ips': [{'ip_address': '1.1.5.177', 'subnet_id': 'e15ec947-9edd-4793-bf0f-c463c7ff2f62'}], 'admin_state_up': True, 'device_id': 'f33db890-7958-440e-b07b-432e40bb4049', 'device_owner': 'network:router_interface', 'name': '', 'project_id': '421ab52e126e45af81a3eb1962613e18', 'mac_address': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'allowed_address_pairs': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'extra_dhcp_opts': None, 'binding:vnic_type': 'normal', 'binding:host_id': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'binding:profile': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'port_security_enabled': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'description': '', 'security_groups': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>}}), {}): Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 247612 function calls (238220 primitive calls) in 16.943 seconds Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: Ordered by: cumulative time Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: List reduced from 1861 to 100 due to restriction <100> Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: ncalls tottime percall cumtime percall filename:lineno(function) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 4/2 0.000 0.000 16.932 8.466 /usr/local/lib/python3.6/dist-packages/neutron_lib/db/api.py:132(wrapped) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 16.928 16.928 /opt/stack/neutron/neutron/common/utils.py:678(inner) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 20/9 0.000 0.000 16.884 1.876 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1317(<genexpr>) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 37/17 0.000 0.000 16.867 0.992 /opt/stack/osprofiler/osprofiler/sqlalchemy.py:84(handler) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 37/17 0.000 0.000 16.860 0.992 /opt/stack/osprofiler/osprofiler/profiler.py:86(stop) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 8/3 0.005 0.001 16.844 5.615 /usr/local/lib/python3.6/dist-packages/neutron_lib/db/api.py:224(wrapped) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 16.836 16.836 /opt/stack/neutron/neutron/plugins/ml2/plugin.py:1395(_create_port_db) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 16.836 16.836 /opt/stack/neutron/neutron/db/db_base_plugin_v2.py:1413(create_port_db) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 16.836 16.836 /opt/stack/neutron/neutron/db/db_base_plugin_v2.py:1586(_enforce_device_owner_not_router_intf_or_device_id) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 16.836 16.836 /opt/stack/neutron/neutron/db/l3_db.py:522(get_router) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 16.836 16.836 /opt/stack/neutron/neutron/db/l3_db.py:186(_get_router) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 34/22 0.000 0.000 16.745 0.761 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/loading.py:35(instances) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 39/8 0.000 0.000 16.727 2.091 /usr/local/lib/python3.6/dist-packages/sqlalchemy/sql/elements.py:285(_execute_on_connection) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 39/8 0.001 0.000 16.727 2.091 /usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/base.py:1056(_execute_clauseelement) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 17/13 0.000 0.000 16.704 1.285 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1310(get) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 20/14 0.001 0.000 16.704 1.193 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1315(_load) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 19/14 0.000 0.000 16.703 1.193 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/loading.py:88(<listcomp>) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 76/23 0.001 0.000 16.699 0.726 /opt/stack/osprofiler/osprofiler/profiler.py:426(_notify) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 39/8 0.001 0.000 16.696 2.087 /usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/base.py:1163(_execute_context) Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 75/23 0.000 0.000 16.686 0.725 /opt/stack/osprofiler/osprofiler/notifier.py:28(notify)
Callers section: all functions or methods that called each function or method in the resulting profiling data. This is restricted by the configured number of top calls to log, as explained in Setting up Neutron for code profiling. Following is a summary example of this section:
Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: Ordered by: cumulative time Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: List reduced from 1861 to 100 due to restriction <100> Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: Function was called by... Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: ncalls tottime cumtime Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /usr/local/lib/python3.6/dist-packages/neutron_lib/db/api.py:132(wrapped) <- 2/0 0.000 0.000 /usr/local/lib/python3.6/dist-packages/neutron_lib/db/api.py:224(wrapped) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /opt/stack/neutron/neutron/common/utils.py:678(inner) <- Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1317(<genexpr>) <- 3 0.000 0.000 /opt/stack/osprofiler/osprofiler/profiler.py:426(_notify) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 16.883 /usr/local/lib/python3.6/dist-packages/neutron_lib/db/api.py:132(wrapped) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 2 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/base.py:69(__init__) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/base.py:1056(_execute_clauseelement) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 16.704 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/query.py:3281(one) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 0 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/query.py:3337(__iter__) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/query.py:3362(_execute_and_instances) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/session.py:1127(_connection_for_bind) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1310(get) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1315(_load) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:2033(load_scalar_from_joined_new_row) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1/0 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/pool/base.py:840(_checkin) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1/0 0.000 0.000 /usr/local/lib/python3.6/dist-packages/webob/request.py:1294(send) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /opt/stack/osprofiler/osprofiler/sqlalchemy.py:84(handler) <- 16/0 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/event/attr.py:316(__call__) Oct 20 01:52:40.767003 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /opt/stack/osprofiler/osprofiler/profiler.py:86(stop) <- 16/0 0.000 0.000 /opt/stack/osprofiler/osprofiler/sqlalchemy.py:84(handler)
Callees section: a list of all functions or methods that were called by the indicated function or method. Again, this is restricted by the configured number of top calls to log. Following is a summary example of this section:
Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: Ordered by: cumulative time Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: List reduced from 1861 to 100 due to restriction <100> Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: Function called... Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: ncalls tottime cumtime Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /usr/local/lib/python3.6/dist-packages/neutron_lib/db/api.py:132(wrapped) -> 1/0 0.000 0.000 /usr/local/lib/python3.6/dist-packages/oslo_db/api.py:135(wrapper) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 16.883 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1317(<genexpr>) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /opt/stack/neutron/neutron/common/utils.py:678(inner) -> 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/neutron_lib/context.py:145(session) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 16.928 /usr/local/lib/python3.6/dist-packages/neutron_lib/db/api.py:224(wrapped) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/session.py:2986(is_active) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1317(<genexpr>) -> 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/default.py:579(do_execute) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 2 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/default.py:1078(post_exec) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 2 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/default.py:1122(get_result_proxy) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 0 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/event/attr.py:316(__call__) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/event/base.py:266(__getattr__) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 15/3 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/loading.py:35(instances) Oct 20 01:52:40.788842 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1317(<listcomp>) Oct 20 01:52:40.791161 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 1 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py:1318(<lambda>) Oct 20 01:52:40.791161 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: 3 0.000 0.000 /usr/local/lib/python3.6/dist-packages/sqlalchemy/util/langhelpers.py:852(__get__)
Setting up Neutron for code profiling¶
To start profiling Neutron code, the following steps have to be taken:
Add he following line to the
[default]section of/etc/neutron/neutron.conf(code profiling is disabled by default):enable_code_profiling = TrueAdd the following import line to each module to be profiled:
from neutron.profiling import profiled_decorator
Decorate each mehtod or function to be profiled as follows:
@profiled_decorator.profile def create_subnet(self, context, subnet):
For each decorated method or function execution, only the top 50 calls by cumulative CPU time are logged. This can be changed adding the following line to the
[default]section of/etc/neutron/neutron.conf:code_profiling_calls_to_log = 100
Profiling code with the Neutron Rally job¶
Code profiling is enabled for the neutron-rally-task job in Neutron’s check
queue in Zuul. Taking advantage of the fact that os-profiler is enabled for
this job, the data logged by the profiled_decorator.profile decorator
includes the os-profiler parent trace-id and trace-id as can be
seen here:
Oct 20 01:52:40.759379 ubuntu-bionic-vexxhost-sjc1-0012393267 neutron-server[19578]: DEBUG neutron.profiling.profiled_decorator [None req-dc2d428f-4531-4f07-a12d-56843b5f9374 c_rally_8af8f2b4_YbhFJ6Ge c_rally_8af8f2b4_fqvy1XJp] os-profiler parent trace-id c5b30c7f-100b-4e1c-8f07-b2c38f41ad65 trace-id 6324fa85-ea5f-4ae2-9d89-2aabff0dddfc 16928 millisecs elapsed for neutron.plugins.ml2.plugin.create_port((<neutron.plugins.ml2.plugin.Ml2Plugin object at 0x7f0b4e6ca978>, <neutron_lib.context.Context object at 0x7f0b4bcee240>, {'port': {'tenant_id': '421ab52e126e45af81a3eb1962613e18', 'network_id': 'dc59577a-9589-4617-82b5-6ee31dbdb15d', 'fixed_ips': [{'ip_address': '1.1.5.177', 'subnet_id': 'e15ec947-9edd-4793-bf0f-c463c7ff2f62'}], 'admin_state_up': True, 'device_id': 'f33db890-7958-440e-b07b-432e40bb4049', 'device_owner': 'network:router_interface', 'name': '', 'project_id': '421ab52e126e45af81a3eb1962613e18', 'mac_address': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'allowed_address_pairs': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'extra_dhcp_opts': None, 'binding:vnic_type': 'normal', 'binding:host_id': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'binding:profile': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'port_security_enabled': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>, 'description': '', 'security_groups': <neutron_lib.constants.Sentinel object at 0x7f0b4fc69860>}}), {}):
Community developers wanting to use this to correlate data from os-profiler
and the profiled_decorator.profile decorator can submit a DNM (Do Not
Merge) patch, decorating the functions and methods they want to profile and
optionally:
Configure the number of calls to be logged in the
neutron-rally-taskjob definition, as described in Setting up Neutron for code profiling.Increase the
timeoutparameter value of theneutron-rally-taskjob in the .zuul yaml file. The value used for the Neutron gate might be too short when logging large quantities of profiling data.
The profiled_decorator.profile and os-profiler data will be found in
the neutron-rally-task log files and HTML report respectively.
