When running a performance test it would be good to spawn off a process to run 'vmstat' which works on linux and solaris (the flags may differ etc) which outputs the amout of CPU use in system/user code and how much is idle together with RAM & IO numbers.
I'd be good to include in each snapshot whatever vmstat numbes we can find so we can see how the box was doing as the test was running.
<sample index="5" ... >
<machine cpuSystem="50" cpuUser="25" cpuIdle="25" ram="44" io="1000"/>
Note that we may wanna make a few different machine monitoring agents using different tools - so lets make it pluggable - let 'em write whatever XML they can - though we should be able to get linux and solaris done (linux only would be fine for now)
To call vmstat we'll need to do a System.exec() then parse the results etc