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Installing Arch on the C720 – Part 3/3 – Fine-tuning

After installation, there are a few things that are not necessary, but might improve your experience with your C720. Below, I’ve posted a few that I’m using. Feel free to suggest other in the comments section.

Install yaourt

yaourt is my favourite AUR wrapper. This is not specific to the C720, but I thought it might be useful nonetheless. I’ve tried to make the installation as simple as possible. Before installing yaourt, the package-query package and the base-devel metapackage must be installed. These commands build and install both.

pacman -S --needed base-devel
cd /tmp
mkdir builds
cd builds
wget https://aur.archlinux.org/packages/pa/package-query/PKGBUILD
makepkg -si
wget https://aur.archlinux.org/packages/ya/yaourt/PKGBUILD
makepkg -si

Improve WiFi and Bluetooth performance

/etc/modprobe.d/ath9k.conf
options ath9k btcoex_enable=1 bt_ant_diversity=1

Enable some GPU power/performance settings

/etc/modprobe.d/i915.conf
options i915 enable_fbc=1 lvds_downclock=1 lvds_use_ssc=1
options i915 enable_psr=1 nuclear_pageflip=1 use_mmio_flip=1

UPDATE: Follow archwiki’s instructions for latest/best settings.

Enable energy savings

# pacman -S tlp
# systemctl enable tlp
# systemctl start tlp

Install the linux-chromebook package

Install zramswap

The amount of RAM in the C720 is pretty limited (specially if you are running Firefox and GNOME3, as I am). Zramswap creates a ramdisk and compresses it using a fast (de)compression algorithm and uses it as swap. This is usually faster than reading from a HDD. In the case of the C720, the seek delays of the SSD are much smaller, but this allows you to skip a swap partition all together (preventing writes into the SSD).

yaourt -S zramswap

In kernel 3.15 and later, you can change the default compression algorithm lzo to lz4. While it’s not clear how much faster is lz4 in real life situations, it’s expected to be faster than lzo (at the cost of a slightly lower compression ratio and larger memory usage during compression). I’ve written a patch for the zramctrl script, it’s available here: patch

Reduce Swappiness

Another thing to help reduce the use of swap is reducing the swappiness.

/etc/sysctl.d/99-sysctl.conf
vm.swappiness=1
vm.vfs_cache_pressure=50

gl;hf

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