Post #1275680
2024-09-02 16:02 UTC
@manawyrm … see LZ4 really being a significant sink of CPU cycles
- once you made the root FS read-only (and thus faster to mount), you can already boot, while, if necessary at all, your system starts mounting your persistent mutable storage. Here, again, same considerations as for the kernel image apply regarding compression: an SD card is so much slower than a CPU, it'd be surprising if the time saved by not reading twice the amount of data was not outweighing the energy cost
Replies (1)
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@funkylab@mastodon.social 2024-09-02 16:12
@manawyrm - are you familiar with scripts/bootgraph.pl? - is putting a minimal initramfs (uncompressed) into the kernel image (compressed) an option? That'd eliminate the time needed for the bootloader to find the root fs / initramfs, and could be very slim (statically linked compiled /bin/init, just enough stuff to mount the immutable main rootfs and maybe kick off things like powering up the modem) - bootlin has a boottime opti slide deck, can't find it, it was cool. Most of above from there