I’m exploring ways to shave a few seconds off of my boot time, and I came across a post that stated, “my initrd is pretty small–doesn’t really load much–and Arch also defaults to using zstd which is also faster to decompress versus gzip.”
What compression does Pop! use for initrd and the kernel? When I run ls -al /boot, I see files such as 14M vmlinuz-6.4.6-76060406-generic and 119M initrd.img-6.4.6-76060406-generic. Are these compressed?
Lastly, is there a way to choose the compression of these boot files without a custom kernel build? Or is what I’m trying to do “off the beaten path” and going to lead to “you have to compile your own kernel from here on out”?
Go to /etc/initramfs-tools/initramfs.conf and change:
compress=gzipto
compress=ztsdand run:
sudo update-initramfs -u -k allThere’s nothing to change. zstd is already the default. Has been from the beginning.
When I check this file, it is already set at
COMPRESS=zstd. However, I’m not sure if it’s working as I think, because the vmlinuz-6.4* kernel file is not a zstd file? Maybe it uses zstd for just a portion of the binary…
I’d be curious to know how uncompressed fairs if you test it. But i think you’re really getting into minimal gains territory…
Pop already uses zstd for its initramfs. You can check by looking at /etc/initramfs-tools/initramfs.conf.
There was an issue where they were considering switching to xz to save space, but when I tried that, it actually made things slower, so I’d avoid that if possible:
I wouldn’t focus on faster decompression.
Disk read speed is almost always the bottleneck. I think you’ll find that smaller file sizes, even if the decompress takes slightly longer, are faster overall because they save disk I/O.
YMMV based on your hardware, of course.
