Experiment Underway To Improve Gentoo's Binary Package Handling With Portage

[NobodyXu]

I am not sure about the usefulness of the -l option. The average load on my 3900X server machine is 2.79 (when not compiling Gentoo packages), which is much smaller than the 5.5 you mentioned - the memory usage on the machine is 27.2GB RAM + 38.8GB SWAP. In this case, the working set size (27.2GB) is 41% of total memory consumption ("sysctl vm.swappiness" is set to 80). PORTAGE_NICENESS=15 is in /etc/portage/make.conf.

You can try zswap, I used it on my 16G laptop so that it can compile firefox, llvm and rust just fine, with the build tree storing in tmpfs.

[NobodyXu]

I have tried zswap, but I wasn't satisfied with the results. Normal swap on a fast NVMe SSD is better than zswap, in my experience. (I am buying NVMe SSDs based on sustained write speeds and I am avoiding SSDs that don't have their own RAM for buffering writes (SSDs relying on "host memory buffer" instead), and thus writing many megabytes from RAM to the swap device to random locations on the SSD device isn't a performance issue.)

My laptop only have 16G of memory, so without zswap it will be quite inefficient despite it has a samsung NVMe SSD.

I used zstd with quite high compression level and it performed quite well.

[binarybanana]

I recommend using zram instead of tmpfs for your build directory. Either using lz4 or zstd, depending on where your bottleneck is (CPU or RAM). That way you can store way, way more source/object files in RAM without hitting storage (like 5x easily). You can also try adding a backing device to zram so that unused or incompressible (configurable) files can be pushed to disk, somewhat like with tmpfs and swap.
The reason I think this is better than tmpfs is that you can fit more in RAM and thus write to disk less often, which is good for longevity if that disk is some kind of SSD, which it probably is.

[skeevy420]

the better solution would be to install a better linux distro or contribute a new build... There is zero reason to use flatpacks or whatever on gentoo... Most builds that have large compile time have a -bin package.

I can't say I disagree with that. Outside of using less dependencies, maybe, unless you were gonna use your Gentoo desktop as a meta-distribution there probably isn't much of a point in Flat on Gentoo due to the -bin packages. I'm assuming there's a line where using Flats over -bins would pull in less dependencies on a minimal setup.