Since 20.10, Ubuntu can be installed on the Raspberry Pi 4 officially. I, who have one to test things, and use it as an entertainment center, I tested the operating system on the raspberry board to check that it works, but it costs much more than when we installed Raspberry Pi OS or Twister OS, for example. Perhaps part of the fault lies with the current GNOME, which doesn't work as well on discrete equipment, but that could change this April, when it launches Ubuntu 22.04.
Yesterday Canonical posted an article in which they talk about the plan to make Ubuntu 22.04 compatible with the 4GB Raspberry Pi 2. But what does this mean? Will operating system performance improve in all scenarios? It is expected that Ubuntu 22.04, with GNOME 42, improves its performance, but the issue they are dealing with here is that they will use a function of the Linux kernel to achieve an optimization that will allow the Canonical system in its main edition work on 4GB RPI2.
Ubuntu 22.04 will arrive in April 2022
What they will use will be zswap.
What is zswap?
To answer this we have to talk about swap files in general.
If you are running any type of Linux system, it is highly likely (and recommended) that you have a swap file assigned to your hard drive or SD card. Swap files act as a kind of overflow for your RAM, caching rarely used pages to free up RAM for more active processes. This allows you to keep working even when your system is using most of the RAM. However, using swap is less efficient than using RAM, as access to the hard drive (or SD card) is slower.
Okay, where does zswap come in? Zswap is essentially a compression tool. When a process is about to be moved to the swap file, zswap compresses it and checks if the new, smaller size still needs to be moved or if it can remain in your RAM. It's much faster to unzip a 'zswapped' page than it is to access the swap file, so it's a great way to get more benefit from systems with smaller amounts of RAM.
Initially, this will improve performance on the 2GB card, but also on the rest, such as the 4GB and 8GB. It will not be activated by default in the desktop version, but I will definitely try Ubuntu again this April on my Raspberry Pi, to see how it feels.