21 years ago today, I posted streamline_config.pl.

Which most of you now know it as make localmodconfig.

@rostedt Thanks for this! It makes it much easier to create a custom config for newly bought hardware, when you can use this to obtain a reasonable seed. 🙂

@notbobbytables You should check out ktest.pl’s make_min_config option. If you have ktest.pl set up, this option will have ktest “bisect” a bunch of configs until it gives you minimal config that boots the board (and optionally runs a test). At the end of the test, if you disable any config, it will not boot.

@rostedt Hmm, only booting seems a little bit too minimal for my regular use case. 😅 Yes, I could add some tests, and it might really come handy if I had to do this regularly.

For me it's really just the occasional new computer, and there booting a stock kernel, localmodconfig and a few manual tweaks are usually enough.

Anyway, it's still worth keeping in mind that this exists, too, so thanks also for this hint. 🙂

@notbobbytables The reason for this option, is that ktest.pl can take a MIN_CONIFG option where you pass the minimal config options that allow your box to boot. This is useful, because you can take someone else’s config (that you may need to debug), use that to build, and ktest.pl will add your min conifg on top, to make sure your box will build.

Now you have a kernel that is as close to possible as the kernel of the person that sent you their config. This is extremely useful when you need to debug their environment.

I should also say that the code is much more complex than what it was back then.

@rostedt `make localmodconfig` is gold for bisecting what used to be a kernel built from a Debian kernel config as each rebuild will now take dozens of minutes instead of several hours. Thank you for this neat tool!