Ubuntu 19.10 To Boot Faster Thanks To LZ4 Compression
After evaluating the different compression options for the kernel image, the Ubuntu developers decided to make use of LZ4 on supported architectures for the kernel image and initramfs. Even with slower rotational storage, the much faster decompression times of LZ4 should yield benefit.
Canonical's Colin Ian King wrote, " In compression size, GZIP produces the smallest compressed kernel size, followed by LZO (~16% larger) and LZ4 (~25% larger). With decompression time, LZ4 is over 7 times faster than GZIP, and LZO being ~1.25 times faster then GZIP on x86... Even with slow spinning media and a slow CPU, the longer load time of the LZ4 kernel is overcome by the far faster decompression time. As media gets faster, the load time difference between GZIP, LZ4 and LZO diminishes and the decompression time becomes the dominant speed factor with LZ4 the clear winner."