Intro

In order to be able to throw pies faster and distribute them even to remote SUSE colonies, we need to build an advanced antimatter-fueled pie hyper-accelerator.

Based on our previous top-secret research, and armed with latest technology acquired from newly established contacts with the alien race of super sentient OBS cross-arch maintainers, we hope we'll be able to accelerate the pies to FTL speeds, making them available across the whole galaxy.

Goals

• Make the Raspberry Pi builds for SUSE Studio faster, to a level which is acceptable for production use.

Steps

• Document how OBS accelerates cross-arch builds using x86 kernel on the host, and kernel hooks inside the arm guest.
• Try to port the same technique to SUSE Studio
• Measure the speed improvements

Results

• The OBS uses an x8664 arch host, with a regular x8664 kernel. The guest registers a binfmt hook with the ARM binary signature via procfs, so that whenever a binary in ARM (or other) format is executed, a special handler takes care of the execution (in this case, qemu-user-arm). This avoids a full arch and allows only userspace emulation. Furthermore, the guest can benefit from KVM, resulting in large speedups.
• We were able to use this mechanism in SUSE Studio to speed up Raspberry Pi image builds ~ 4 times, from ~ 40 to ~ 10 minutes. Also, as the x86 and ARM builds can use the same build environment, backend code was simpilfied.

Further work

• Clean up the backend code and integrate the build environment changes into 'upstream'.
• QA