In the hazy past, the kernel community struggled mightily with a rather vexing issue: though scheduling algorithms and their implementations – the early 2.6.0 O(1) scheduler, and a little later (with 2.6.23), the Completely Fair Scheduler (CFS) – promised, well, completely fair scheduling, it really wasn't. Think about this for a moment: let's say you are logged into a Linux server along with nine other people. Everything else being equal, it is likely that processor time is (more or less) fairly shared between all ten people; of course, you will understand that it's not really people that run, it's processes and threads that run on their behalf.
For now at least, let's assume it's mostly fairly shared. But, what if you write a user space program that, in a loop, indiscriminately spawns off several new threads, each of which perform a lot of CPU-intensive work (and perhaps as an added bonus, allocates...
