---
title: Gentoo Tips, Tricks & Shenanigans
description: These are Gentoo relevations which surprised me at some point, along with nice to haves.
published: true
date: 2022-04-30T20:10:31.949Z
tags: gentoo, performance
editor: markdown
dateCreated: 2021-09-02T08:10:07.601Z
---

Below are stuff I found out about Gentoo.
# Moving package from Testing to Stable

Gentoo's testing branch (`~arch`) is actually quite stable. However, in case you'd like to keep something on stable for whatever reason (I encountered this with the kernel, trying to Clang it), you can mask the `~amd64` keyword under `/etc/portage/package.accept_keywords/your_package`. Example:
```bash
/etc/portage/package.accept_keywords/gentoo-sources:
sys-kernel/gentoo-sources -~amd64
```
That is, if your `/etc/portage/make.conf` contains ~amd64, you can un-`~amd64`-it this way. Noice!
# Clang

Clang is an LLVM frontend and an alternative to GCC. Clang has recently [surpassed GCC](https://www.phoronix.com/scan.php?page=article&item=clang12-gcc11-icelake&num=6) performance wise, as well as being easier to set up for goodies like LTO.

[Gentoo's wiki page](https://wiki.gentoo.org/wiki/Clang) lays out how to use Clang as a system compiler instead of GCC - but note the few caveats below:
> READ THE INSTRUCTIONS CAREFULLY! the order is crucial and is not chronological!
{.is-danger}

- All DE's tested (KDE5, GNOME3) require `samba`, and `samba` requires GCC's own `libunwind`. Hence, when following instructions above, do not use `llvm-libunwind` (unfortunately). This is only relevant for GUI installations - servers are fine.
- Clone the [Portage Git repository](http://git.pukeko.xyz/shmick/portage.git) for necessary overrides back to GCC (such as Python3, GNU libc).

- Use `flto=thin`. It's easy and it works great.
- > Use `LDFLAGS` per compiler - when adding Clang's `LDFLAGS` to the global `make.conf`, GCC also reads them (and fails!).
{.is-warning}

- Use ninja for faster compile times.
- if following [Compiling on the RAM](/Compiling_on_RAM) When building Clang itself, unmount `/var/tmp/portage` - it doesn't play nicely.

Happy compiling!
# Virtualizing with UEFI on QEMU

When trying to create a UEFI VM on `virt-manager`, some settings will lead to a blank screen. In order to use UEFI:

- emerge the UEFI firmware - `sys-firmware/edk2-ovmf`
- restart libvirtd if running
- when creating a VM, select the Q35 chipset (440FX does not work), and use the `secure_code` option - `UEFI x86_64: /usr/share/qemu/edk2-x86_64-secure-code.fd`.

> Reference: https://forums.gentoo.org/viewtopic-t-1066336-start-0.html
{.is-info}

# The `Makefile` is just a file!
You can read it! you can tweak it! yay!
> Thanks, [Gentoo-folk](https://forums.gentoo.org/viewtopic-t-1140180.html)!