How to speed up Linux kernel compilation?

Do not do make menuconfig for every change you make to the sources, because it will trigger a full compilation of everything, no matter how trivial your change is. This is only needed when the configuration option of the kernel changes, and that should sheldom happen during your development.

Just do:

make

or if you prefer the parallel compilation:

make -j4

or whatever number of concurrent tasks you fancy.

Then the make install, etc. may be needed for deploying the recently built binaries, of course.

Another trick is to configure the kernel to the minimum needed for your tests. I've found that for many tasks a UML compilation (User Mode Linux) is the fastest. You may also find useful make localmodconfig instead of make menuconfig to start with.

1. Use make parallel build with -j option
2. Compile for the target architecture only, since otherwise make will build the kernel for every listed architecture.

i.e. for eg instead of running:

make

run:

make ARCH=<your architecture> -jN

where N is the no of cores on your machine (cat /proc/cpuinfo lists the no of cores). For eg, for i386 target and host machine with 4 cores (output of cat /proc/cpuinfo):

make ARCH=i386 -j4

Similarly you can run the other make targets (modules, modules_install, install) with -jN flag.

Note: make does a check of the files modified and compiles only those files which have been modified so only the initial build should take time, subsequent builds will be faster.

You do not need to run make menuconfig again every time you make a change — it is only needed once to create the kernel .config file. (Or possibly again if you edit Kconfig files to add or modify configuration options, but this certainly shouldn't be happening often.)

So long as your .config is left alone, running make should only recompile files that you changed. There are a few files that must be compiled every time, but the vast majority are not.