OSProfiler provides a tiny but powerful library that is used by most (soon to be all) OpenStack projects and their python clients. It provides functionality to be able to generate 1 trace per request, that goes through all involved services. This trace can then be extracted and used to build a tree of calls which can be quite handy for a variety of reasons (for example in isolating cross-project performance issues).

• Free software: Apache license
• Documentation: http://docs.openstack.org/developer/osprofiler
• Source: http://git.openstack.org/cgit/openstack/osprofiler
• Bugs: http://bugs.launchpad.net/osprofiler