First thing's first, you're going to need a system with DTrace. This likely means Solaris (or one of its decedents), OS X, or a BSD variant.  There doesn't appear to be Dtrace available for Linux :(

Secondly, you'll exposing a significant security volunterability if you change the binding port away from localhost. Please only do so if you're confident of your network. 

Still with us? Good. 

For this tutorial you'll also need: 

    node - http://nodejs.org/#download
    npm - https://github.com/isaacs/npm
    node-libdtrace - https://github.com/bcantrill/node-libdtrace
    Socket.IO – “npm install socket.io”
    express - npm install express


Once these are installed simply run heat tracer as root (dtrace requires root for it's kernelspace trapping goodness):
    
    sudo node heat_tracer.js 


That's it, browse to http://localhost/heat_tracer.html and enjoy looking at your syscall latency.


This code is released under the MIT license. See LICENSE file for details..