Plan to test parallel rustc

announcements
18

So I have an 4 core, 8 logical processes, win10 laptop. So here are my numbers for compiling cargo:

cargo> cargo clean

cargo>cargo +nightly-2019-12-17 check -Ztimings => 1m 47s
cargo>cargo +nightly-2019-12-18 check -Ztimings => 1m 44s 

cargo>cargo +nightly-2019-12-17 build -Ztimings => 1m 48s
cargo>cargo +nightly-2019-12-18 build -Ztimings => 1m 43s

cargo>cargo +nightly-2019-12-17 build --release -Ztimings => 6m 44s
cargo>cargo +nightly-2019-12-18 build --release -Ztimings => 6m 44s

git of timing files