Ucore kernel snap size: netronome smartnic fw

[Sertac TULLUK]

[ Impact ]

Pi kernel snaps are big in part due to included firmware binaries. A lot of these binaries are not needed/required by the Pi kernel. The size of the snap has a negative impact on boot speed.

[ Fix ]

Parse modinfo data from all modules to determine the list of required firmware files and remove the ones that are not necessary during snap build time.

[ Test Case ]

On core20 before:
$ du -sh /lib/firmware/
602M /lib/firmware/

And after:
$ du -sh /lib/firmware/
58M /lib/firmware/

[ Where Problems Could Occur ]

We might accidentally drop needed firmware which might render the relevant HW unusable. Firmware load failures should be visible in the kernel log though.

[ Original Description ]

The size of the pi-kernel snap for UC20 is 254Mbytes (compressed) and
794Mbytes (uncompressed).

569Mbyte of this is caused by FW

140Mbyte -> Netronome SmartNIC

Removing unreferenced FW and/or reducing number of drivers & their FW has exponential reduction of disk space usage.

Additionally, downloaded image will be smaller; and storing 3x kernel snaps for upgrades will be smaller.

Even more, snap seeding will be faster, so boot time will be faster.

So it will be a nice gain in multiple aspects: download image, boot image, upgrade image, reboot image, start using image.

stulluk ~/tmp $ ls -lah pi-kernel_353.snap
-rw------- 1 stulluk stulluk 254M Kas 8 13:57 pi-kernel_353.snap
stulluk ~/tmp $ cd pikern/
stulluk ~/tmp/pikern $ du -sh
794M .
stulluk ~/tmp/pikern $ cd firmware/
stulluk ~/tmp/pikern/firmware $ du --block-size=MiB --max-depth=1 . | sort -rn
569MiB .
140MiB ./netronome
40MiB ./amdgpu
34MiB ./intel
25MiB ./liquidio
24MiB ./qcom
20MiB ./qed
19MiB ./brcm
12MiB ./mellanox
12MiB ./dpaa2
12MiB ./ath10k
...

[Dimitri John Ledkov (xnox)]

Netrome smartnic is 10x the price of RPi. It is unlikely that one will run ovs on armhf successfully. And i think even arm64 variants of RPi may be overwhelmed by ovs as well.

Imho it makes sense to disable Netrome smartnic driver in the raspi kernel flavour and also remove/filter netrome firmware from the raspi kernel snap.

[Rolf Leggewie (r0lf)]

I requested for a more modular and leaner firmware package a long time ago in bug 1958518

[Juerg Haefliger (juergh)]

For snaps this was actually fixed a while ago:
https://git.launchpad.net/~canonical-kernel-snaps/+git/kernel-snaps-uc20/commit/?id=6d91407c39bfe31caf56291ce445f0084315f2b5