The Linux deadline scheduler supports realtime systems where
applications need to
be sure of getting their work done within a specific period of time. It
allocates CPU time to deadline tasks in such a way as to ensure that each
task’s specific timing constraints are met.
However, the current
implementation does not work well on asymmetric CPU configurations like Arm’s
big.LITTLE. Dietmar Eggemann recently posted
a patch set to address this problem by adding the notion of CPU
capacity to the deadline scheduler.

Source: LWN.net – [$] Capacity awareness for the deadline scheduler