[security-dev] Picketbox performance improvements

Hi, I have been benchmarking Wildfly upstream, and with the exception of the Weld listener (that I am about to try and fix), I am seeing the creation of the security context as by far the most expensive part of the web request chain. Firstly a bit about the tests, basically it is possible to run Undertow in pipelining mode, where if you send it pipelined HTTP requests it will buffer the responses and batch them. This is not super useful in practice, but what it does allow me to do is basically take most of the IO component out of a web request, and just look at which bits of the web request chain are consuming the most CPU. The issues I am seeing are: - Some unnecessary AccessController.doPrivilidged calls - A reflection call on every request to lookup the constructor of the security context class I have provided a patch to address both of these, by adding a guard around the AccessController calls, and by caching the constructor used for the default security context class. I think it may even be worthwhile taking this one step further, and using generated bytecode to create the class. Normally I would consider this overkill but security context creation happens on every request, so if we are serious about performance we should be trying to make it as cheap as possible. To give you an idea of how much this affects the total cost of the Servlet pipeline: Current WF upstream (without Weld): 134k req/sec After removing the AccessController calls: 158k req/sec Adding constructor caching: 171k req/sec Note that the speedup will not be as big for more realistic workloads, however it will still be significant. Stuart