By default when you emerge a long list of packages in Gentoo you have to download each package completely before the build process can begin. This can be a large bottleneck, especially if your internet connection is not very fast.
Luckily Portage has a great solution.
Go to the file /etc/make.conf and add “parallel-fetch” to the FEATURES variable like this.
FEATURES="parallel-fetch"
If the FEATURE variable already exists add “parallel-fetch” to the end separated by whitespace.
FEATURES="sandbox parallel-fetch"
From now on Portage will fetch the source files for the next package in the list even while it is compiling another package.
To see parallel fetch progress, run this command.
$ tail -f /var/log/emerge-fetch.log