Gentoo MAKEOPTS question

andrewwalker27 · l33t Joined: 27 Jun 2005 Posts: 660

I'm doing a fresh install on my new machine which has 16Gb of RAM and an AMD Ryzen 7 3700X and I'm unable to decide what value to use. The docs infer that MAKEOPTS="-j9" is the correct number but previous experience makes me cautious.
I previously had a 6 core machine which had -j7 set and the machine kept locking up every time I tried compiling firefox, I think it was a lack of memory issue and took me ages to diagnose and I don't want to make the same error. I'd assumed, incorrectly, the swap disk would solve memory shortage but I was wrong, is there any way of limiting ram usage?
Ideally I'd like to prevent gcc from using all the ram available without hitting the compile time too badly, I could reduce the -j value but that would probably do precisely that.
Anybody got any suggestions?

alamahant · l33t Joined: 23 Mar 2019 Posts: 673

Hi
The literature is that each job should be assigned 1.5-2 Gigs of ram.
I prefer -j4 so I can leisurely use my system while updating or emerging.
maybe you can use portage on tmpfs.
In /etc/fstab add a line

Juippisi · Developer Joined: 30 Sep 2005 Posts: 510 Location: /home

You can use package.env to reduce MAKEOPTS for specific packages,
https://wiki.gentoo.org/wiki//etc/portage/package.env

If you use tmpfs you might indeed hit memory problems when compiling bigger packages, since they take multiple gigabytes to store the temporary files in memory, then compiling eats its own share. 16 GB is too little for the big ones, but should be just fine for that 90 %.