FYI: Faster AccessController stack decoder

[Gary Benson <gbenson at redhat dot com>]

Hi all,

The stack walking code in VMAccessController.getContext() stops when
it encounters calls to AccessController.doPrivileged(), meaning that
parts of the stack trace are unused.  This commit adds a custom stack
decoder that mirrors this logic such that only the frames which are
used will be decoded.  I've been using Tomcat as a benchmark, and this
commit improves our performance from 1800 to 2100 requests per second.
Sadly this is nowhere near the 5800 we do without a security manager :/

Cheers,
Gary

Attachment: stack-decoder.patch
Description: Text document