[javagram]

Interesting article but I can’t understand why cross compilation is dismissed.

It could have been improved by some performance benchmarks showing cross compilation performance in comparison with this emulation based solution. I find it hard to believe it makes sense to emulate when native performance is available.

[jcoffland]

Cross compiling is a lot more difficult to set up. Emulation let's you use much of the target system's tools as is. Cross compiling means you have to build all of those tools for the host system.

For example, with the RaspberryPi I can grab a Raspbain image, add binfmt and qemu on my host and with a few small changes to the image chroot in to a ready made build environment for the Pi that's faster and more convenient than compiling on the Pi. Setting up a cross compile environment for the Pi is much harder.

Docker is totally unnecessary BTW.

[jrockway]

I've honestly never had a problem cross-compiling for the Raspberry Pi. I learned my lesson back when it first came out; I needed a new ntpd and it took 24 hours to build on the Pi. I then realized the settings were wrong and spent about 20 minutes setting up the cross-compilation machinery on my x86 Linux box instead of waiting another day. "apt-get install crossbuild-essential-armhf" and some configuration and your build is done in seconds. Well worth it.

Modern languages are even easier. I can build a Go binary for the Raspberry Pi by setting one or two environment variables; "GOARCH=arm GOOS=linux go build ./whatever". Wonderful.

The Raspberry Pi has improved since the original. I recently needed llvm compiled from source and it only took on the order of hours on a Pi 4. (GCC was unusable, though; uses too much memory. Had to use clang from the package manager to build a new LLVM. The efficiency was impressive.)

[jcoffland]

Finding the right parameters to cross compile each dependency you need is tedious. Sure some packages are easy to cross compile but it's much easier to set up an emulated build environment and then compile everything normally.

[rubicks]

Concur. Docker the runtime is unnecessary, but the day I started with Dockerfiles was the day I stopped building my chroots with Makefiles.

[jcoffland]

A Makefile tracks a dependency tree and rebuilds what has changed. Docker has a dependency list and has to rebuild everything following any change. Seems to me like we've gone backwards.

[rubicks]

I have used docker with qemu syscall emulation to build various projects for foreign architectures. I really wanted to cross-compile, but the build tools chosen by those projects made it infeasibly difficult.