Is the following paragraph from man 5 make.conf up to date?
Use this variable if you want to use parallel make. For example, if you have a dual-processor system, set this variable to "-j2" or "-j3" for enhanced build performance with many packages. Suggested settings are between CPUs+1 and 2*CPUs+1. In order to avoid excess load, the --load-average option is recommended. For more information, see make(1). Also see emerge(1) for information about analogous --jobs and --load-average options.
It would be nice if there could be a hint about lowering the number of threads if there are out of memory problems, e.g.:
If you experience out of memory problems when running emerge, lower the number of threads in make.conf or on a per package base in package.env . Most packages will be merged without memory problems if you limit the thread count to RAM/2GB.
See also: https://wiki.gentoo.org/wiki/Knowledge_Base:Emerge_out_of_memory
Yeah, this is inconsistent with modern advice, which is:
... given modern compiler (often C++) jobs can take up to 2GB per job.