Linux performance optimizations

This is a collection of optimizations that I've gathered over time to make my Arch Linux systems boot faster and run smoother.

Testing

This has been tested on all of my systems, please have an arch install usb ready in case something goes wrong. My systems are:

Name	CPU	RAM	Storage
ThinkPad T14 Gen 2	AMD Ryzen 7 PRO 5850U	2x16GB DDR4	2TB WD Green SN350 NVMe
Main PC	Intel Core i5-10400F	2x16GB DDR4	1TB Lexar NM710 NVMe + 4TB HDD
ThinkPad T470s	Intel Core i5-7300U	24GB DDR4	1TB i-dont-remember NVMe

Setting up Booster initramfs

1. Install booster

yay -S booster

2. Edit the /etc/booster.yaml file so it applies ZSTD compression

Other options

You might want to enable module stripping if you're feeling adventurous. It will make the initramfs smaller, but it might break things.
To enable it add strip: true to the booster.yaml file.

compression: zstd

3. Regenerate the initramfs

sudo /usr/lib/booster/regenerate_images

4. Adding a pacman hook to regenerate the initramfs on kernel updates. Run sudo nvim /etc/pacman.d/hooks/90-booster-rebuild.hook and add the following:

[Trigger]
Operation = Install
Operation = Upgrade
Type = Package
Target = linux-*
# Change to just `linux` if you only use the default kernel

[Action]
Description = Regenerating Booster initramfs...
When = PostTransaction
Exec = /usr/lib/booster/regenerate_images

Setting up EFIStub booting (removing the bootloader)

1. Forward your current kernel parameters to a file readable by systemd-ukify

cat /proc/cmdline | sudo tee /etc/kernel/cmdline

2. Install systemd-ukify

yay -S systemd-ukify

3. Build the EFI stub image. I am using the linux-cachyos kernel, if you're using a different one, look for the appropriate files in /boot/

sudo ukify build \
    --linux=/boot/vmlinuz-linux-cachyos \
    --initrd=/boot/amd-ucode.img \
    --initrd=/boot/booster-linux-cachyos.img \
    --cmdline="@/etc/kernel/cmdline" \
    --output=/boot/EFI/linux-cachyos/arch-linux-cachyos.efi

4. Add a new boot entry to UEFI

IMPORTANT

Make sure to change /dev/nvme0n1 and -p 1 to the appropriate disk and partition where your EFI System Partition is located.
You can check this with lsblk, and looking for the partition with the /boot mountpoint. In my example, it's /dev/nvme0n1p1.

❯ lsblk 
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
zram0       253:0    0    4G  0 disk [SWAP]
nvme0n1     259:0    0  1.8T  0 disk 
├─nvme0n1p1 259:1    0    1G  0 part /boot
└─nvme0n1p2 259:2    0  1.8T  0 part /

sudo efibootmgr -c -d /dev/nvme0n1 -p 1 -L "ArchLinux" -l 'EFI/linux-cachyos/arch-linux-cachyos.efi'

5. Add a pacman hook to rebuild the EFI stub image on kernel updates. Edit this to match your kernel and initramfs paths. Run sudo nvim /etc/pacman.d/hooks/95-ukify.hook and add the following, replacing the paths with the ones that match your system:

[Trigger]
Operation = Install
Operation = Upgrade
Type = Package
Target = linux-cachyos

[Action]
Description = Rebuilding the UKI...
When = PostTransaction
Exec = /usr/bin/systemd-ukify build --linux=/boot/vmlinuz-linux-cachyos --initrd=/boot/amd-ucode.img --initrd=/boot/booster-linux-cachyos.img --cmdline="@/etc/kernel/cmdline" --output=/boot/EFI/linux-cachyos/arch-linux-cachyos.efi

6. Reboot, and remove your old bootloader from the system, it's no longer needed as the system will boot directly from the EFI stub.

Optimizing NetworkManager

This only applies if you are using NetworkManager, and cannot just replace it with systemd-networkd.

1. Disable the wait-online service. This will make your system boot slightly faster, but it will not wait for the network to be fully up before finishing the boot process. This doesn't matter in 99.9% of cases.

sudo systemctl disable NetworkManager-wait-online.service

Using ZRAM

ZRAM creates compressed blocks of RAM that can be used as swap. This is beneficial for all systems.

1. Install zram-generator

yay -S zram-generator

2. Create a configuration file for zram-generator. Run sudo nvim /etc/systemd/zram-generator.conf and add the following:

[zram0]
zram-size = min(ram / 2, 4096)
compression-algorithm = zstd

3. Reload daemons and start the zram swap

sudo systemctl daemon-reload
sudo systemctl enable systemd-zram-setup@zram0.service
sudo systemctl start systemd-zram-setup@zram0.service

4. Verify that the zram swap is active

sudo systemctl status systemd-zram-setup@zram0.service

Kernel parameters

How to edit

Edit the /etc/kernel/cmdline file to add or remove kernel parameters.

1. Using the ADIOS elevator

elevator=adios

2. Overall optimizations

rw zswap.enabled=0 loglevel=3 quiet