Very often I’m in the middle of an interactive rebase and while editing a commit I remember I should have changed a commit that I initially didn’t mark on the rebase todo. If you tried to git-rebase again you would notice it’s not possible due to git’s bookkeeping of the current rebase.

In the past what I usually did was to either 1) Continue the rebase and then rebase again to fix the previous commit or 2) Create a fixup commit with git commit --fixup and then rebase again with --auto-squash.

Now I have a helper …

Generating a new rootfs from scratch in order to test changes to early parts of the software stack or just to have a pristine environment is something I needed several times in the past.

Since I use Archlinux in my desktop something that I like is to have a similar environment in the target test rootfs. I decided to re-use and improve a script from Kay Sievers to create an installer that can be booted as a VM, as a container or in bare metal: arch-installer.sh. Originally  it was a script to bootstrap a Fedora image and I think …

For those who don’t know, dolt is a wrapper and replacement for libtool on sane systems that don’t need it at all. It was created some years ago by Josh Triplett to overcome the slowness of libtool.

Nowadays libtool should be much faster so the necessity for dolt should not be as big anymore. However as can be seen here, it’s not true (at least in libtool > 2.4.2). Yeah, this seems a bug in libtool that should be fixed. However I don’t like it being any more complicated than it should.

After talking to …

An alternative headline is: “how to show your wife how much you love her, the geek way”.

From 17 to 22 of September I was in New Orleans participating in the discussions of the Linux Plumbers Conference, which has already turned into one of my favorite conferences. Lots of fun, talking to great people and good discussions about systemd, containers, cgroups, kernel modules, etc. However as the headline indicates this blog post is not to talk about the conference but rather about a toy the Intel booth was giving out: a fan with 7 leds in its propeller. See below …

One thing that caught my interest lately was the implementation of hash tables, particularly the algorithms we are currently using for calculating the hash value. In kmod we use Paul Hsieh’s hash function, self entitled superfast hash. I fell troubled with anything that entitles itself as super fast, especially given the benchmarks provided are from some years ago, with older CPUs.

After some time spent on benchmarking and researching I realized there were much more things to look after than just the hash function. With this post I try to summarize my findings, showing some numbers. However do take …

First of all, a little digression about build systems.

I’d like to clarify that I’m no lover of autotools. But I’m no lover of any other build system, neither, and autotools is used on several open source projects, including most of the ones I participate. It’s easily copied and pasted by new projects. It’s known by distro maintainers how to hack on it to work on different scenarios like cross-compilation, distribute build across machines, different compilers, rpath, etc etc. Moreover, from my experience, project maintainers usually dislike changing the build system because it causes several …