[esotericn]

The entire Linux kernel source tree will trivially fit in tmpfs in RAM.

On one of these systems I'm fairly sure you could just whack the entire thing in /tmp and -j64 it, the compile artifacts aren't that big either.

[trunc]

I've done builds in /dev/shm/ on Xeon and Threadripper with only a trivial speed-up. If it can fit in tempfs, make/cc can just load it all into RAM anyway, so I guess you only reduce the build time by the time it takes for the first read. Which would explain why '-j' on a big codebase tends to trigger my OOM killer.