Bootstrap takes a very long time due to lack of parallelism
Motivation
Bootstrapping ghc currently takes an extremely long time. This is a problem for both contributors who want to change the compiler as well as just plain users of the compiler who for one reason or another end up having to build the compiler.
Proposal
Looking at the resource usage during the build, it becomes apparent that most of the time the build system is utilizing just 1 or 2 cores at a time. Improving build parallelism of GHC I think is likely something that would give the most bang for the buck for a modern developer or user of GHC.