Ubuntu 18.10 Looking At LZ4-Compressed Initramfs Image By Default

[jacob]

When would you need to be able to decompress an initramfs that wasn't paired and thus generated with the kernel you're trying to boot? Also, the Ubuntu Kernel by default enables all decompression algorithms for initramfs.

I'm not really familiar with the inner workings of initramfs and the early boot process, but maybe it also affects the boot loader (GRUB etc.), not just the kernel?

[nils_]

Let's change stuff for the sake of changing stuff. Backwards compatibility is a Microsoft thing, it has to be avoided at all costs.

When would you need to be able to decompress an initramfs that wasn't paired and thus generated with the kernel you're trying to boot? Also, the Ubuntu Kernel by default enables all decompression algorithms for initramfs.

[eydee]

Let's change stuff for the sake of changing stuff. Backwards compatibility is a Microsoft thing, it has to be avoided at all costs.

[TumultuousUnicorn]

I'm using an uncompressed initramfs on Arch: decompression time = 0s.
But yeah, only useful on a SSD.

[rene]

No reason to do LZ4 for initrd, unless you have really weak CPUs. LZ4 compression ratio is poor. LZ4 is really only useful if your compression/decompression performance matters A LOT. For example, for transparently compressing network traffic at >200 MB/s on the fly.

ZSTD is much better for initrd IMO. It has both faster performance, and compression ratios that are similar or better compared to gzip.

ACK +1 from me, testing zstd initramfs since a month or two, https://t2sde.org ,-)

[coder111]

No reason to do LZ4 for initrd, unless you have really weak CPUs. LZ4 compression ratio is poor. LZ4 is really only useful if your compression/decompression performance matters A LOT. For example, for transparently compressing network traffic at >200 MB/s on the fly.

ZSTD is much better for initrd IMO. It has both faster performance, and compression ratios that are similar or better compared to gzip.

[profoundWHALE]

1 second off of what? Their PC with 8 cores and SSD or 1 second off a PC with a HDD and 2 cores?

On my old laptop the initramfs extraction time decreased from ~1.2s to ~0.24s: (with lz4)

[cl333r]

90 seconds - 1 = 89 for me. If this feature doesn't herald the year of the Linux desktop then I don't know what does.

[phoronix]

Phoronix: Ubuntu 18.10 Looking At LZ4-Compressed Initramfs Image By Default

With Ubuntu 18.10 being the release after an LTS cycle, it's shaping up to be another big feature period. They have already been discussing Zstd-compressed Debian packages for Ubuntu 18.10 while the latest proposal for this next cycle is on switching from Gzip to LZ4 for the default kernel initramfs image...

http://www.phoronix.com/scan.php?page=news_item&px=Ubuntu-Initramfs-LZ4-Plans