The Brain Fuck Scheduler v0.456 by Con Kolivas.

A single shared runqueue O(n) strict fairness earliest deadline first
design.

Excellent throughput and latency for 1 to many CPUs on desktop and
server
commodity hardware.
Not recommended for 4096 cpus.

Scalability is optimal when your workload is equal to the number of CPUs
on
bfs. ie you should ONLY do make -j4 on quad core, -j2 on dual core and
so on.

Features SCHED_IDLEPRIO and SCHED_ISO scheduling policies as well.
You do NOT need to use these policies for good performance, they are
purely
optional for even better performance in extreme conditions.

To run something idleprio, use schedtool like so:

schedtool -D -e make -j4

To run something isoprio, use schedtool like so:

schedtool -I -e amarok

Includes configurable SMT-nice support for better nice level and
scheduling
policy support across SMT (aka hyperthread) sibling CPUs.

Includes accurate sub-tick accounting of tasks so userspace reported
cpu usage may be very different if you have very short lived tasks.

-ck