Additional optimizations

furkantokac / buildroot

Buildroot fork customized for RPI3, iMX6, TK1, Qt, FastBoot.

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Additional optimizations #8

Closed IronOxidizer closed 3 years ago

IronOxidizer commented 4 years ago

I'm attempting a similar project for the Raspberry Pi Zero. Here are some additional optimizations I have found:

Use LZ4 kernel compression for faster boot times
- https://events.static.linuxfound.org/sites/events/files/lcjpcojp13_klee.pdf
Use fastboot mount option for F2FS to improve boot times
- https://www.kernel.org/doc/Documentation/filesystems/f2fs.txt
- https://linux-f2fs-devel.narkive.com/cND2je9J/f2fs-mount-o-sync-sync-and-cut-off-power
- I noticed that the very first boot after a clean flash with F2FS is usually 10% faster than sequential boots. This flag fixes this issue resulting in a speed up (0.5s in my case).
Statically compile with musl libc to produce smaller binaries that load faster
- https://www.etalabs.net/compare_libcs.html

furkantokac commented 4 years ago

Thanks for your contribution!

I don't have experience with RPI Zero but it should be similar to RPI3 since they use same series of SoCs. For RPI3, the main bottleneck is the hardware. It takes 1.5sec to boot with a graphic support, 1.0sec to without graphic support. There are some new works about open-source firmware for the RPI3, I'm following them. If we can solve this problem, there is a big potential even faster boot time.

IronOxidizer commented 4 years ago

Mind pointing me in the direction of that open-source RPi firmware?

I've been experimenting with the cut down versions of the firmware (start_cd.elf and fixup_cd.elf). I've managed to save 0.3s with it but It's not practical for all uses as it removes a large amount of GPU functionality.

You can check it out here: https://github.com/IronOxidizer/instant-pi

One more thing, kernel 5.9 recently added support for ZSTD compression which provides similar decompression speeds at a much higher ratio than LZ4. This should also improve performance, especially when initramfs is packaged with the kernel image and compressed with ZSTD.

furkantokac commented 3 years ago

Mind pointing me in the direction of that open-source RPi firmware?

This is the main issue. If I focus on more progress, I work on in. That would be very cool!

Image compression you mention does not really make big impact on the current image.

I checked your repo, its cool. Good job 👍🏻