Hi - I'm working on a low-level enabler library for LWP support (64-bit Linux - I don't have a Windows8 system). It is available from my profiling tools page:
http://gorton-machine.org/rick/PathProfiling
Let me know if you find it useful.
An update: there is now an enhanced version of that particular library, along the the necessary Linux kernel work (in the form of a unified source patch) to fully enable XSAVE/XRSTOR on LWP capable systems.
The library is in GPL (full GPL, not LGPL) form.
Location: http://gorton-machine.org/rick/PathProfiling
Regards,
Richard Gorton