NtQuerySystemInformation needs a little bit more flesh for SystemProcessorPerformanceInformation

[Juan Lang]

> This Reserved1[0] is the DPC Time but I'm wondering what values from
> /proc/stat to use here (remainder[0] is I/O wait). We could always make up
> something of course but being accurate would be nicer.

DPC Time has no equivalent in /proc/stat.  It's an NT thing.  Making
something up is the only appropriate thing, unless we start doing
something special with DPCs someday.
--Juan