There has been a frequently encountered problem with vztop on OpenVZ making the tool totally useless - it worked perfectly except for it didn't show virtual machine IDs for processes. Instead of actual numerical ID, it showed "N/A" in the VEID column.
So I spent an hour or so debugging, and it turned out that vztop, when requested to show the VEID column, didn't set a flag which enabled collection of VEIDs and other data. While diving into vzprocps source, I also made vztop show VEID by default. The result is this simple patch against vzprocps 2.0.11-2.
Apply with patch -p1 <vztop_veid.txt
If you need to debug a problem with some piece of software, I'm for hire at Massive Scale. I have never seen vzprocps source code before and still the solution was available in just 1 hour of work. That's $70. Would your $15/h programmer solve the problem as efficiently?