About AppImage slow startup time.

[Samueru-sama]

Hi @sinelaw, I saw this blog post you made: https://getfresh.dev/docs/blog/packaging-for-linux/

I do release an AppImage, but it's extremely slow to run because of the squashfs FUSE-mount on-demand, which makes bringup time unacceptably slow.

This is a problem we have a fixed long ago by using DwarFS instead of SquashFS.

Plus the uruntime offers the option to keep the appimage mounted forever, which means only the very first start would have a measurable delay, all other launches will be as instant as if the appimage was extracted: pkgforge-dev/ghostty-appimage#54

• ~1.3 seconds cold launch.
• ~985 ms for all next launches.
• ~890 ms for the native archlinux package.

(The 100ms difference is due to GTK4 not liking a long XDG_DATA_DIRS which the appimage sets)

Also, since my binary requires some minimal libc version, it isn't actually universally portable (so for a 2-3 year old distro it might not work)

This issue is also solved by our tools. 1 2

Why does my app need FUSE?!

It doesn't, the uruntime has a fallback to mount namespaces and finally fallback to extract and run in /tmp if that isn't possible either.