Ubuntu is one of the popular desktop Linux distributions, and the upcoming Ubuntu 22.04 release has some performance tweaks for the Raspberry Pi. An official blog post announced that the next release of Ubuntu Desktop will bring new performance enhancements to Raspberry Pi boards, enabling a viable desktop experience on the 2GB model of the Raspberry Pi 4.
The main change is that Ubuntu on the Raspberry Pi uses the zswap function of the Linux kernel by default, which can compress memory blocks instead of relying entirely on swap files (virtual memory). This feature reduces the amount of I/O operations that may occur, resulting in a better experience with the Raspberry Pi’s low-speed SD card.
According to reports, zswap is essentially a compression tool. When a process is about to be moved to a swap file, zswap compresses it and checks to see if the new page still needs to be moved, or it can remain in memory. Unzipping a “zswapped” page is much faster than accessing a swap file, and yields higher yields.
However, memory compression also increases CPU usage, so it won’t work on older Raspberry Pis with weaker CPUs. Ubuntu 22.04 is scheduled to be released in April, and the changes will be enabled by default on all Raspberry Pi 4 devices, including the Pi 400.