Other articles

  1. Using evemu to simulate input devices

    I’m doing some experiments to make the remote controller of Parrot’s Disco drone (SkyController 2) to work with ArduPilot. I will talk more about this in another post. This one is basically about a nifty tool I’ve found that I didn’t know existed: evemu. I always used evtest to debug the input system in Linux.

    SkyController 2 runs Linux and exposes all the sticks and buttons as an evdev device. I developed a tool to serve as a general-purpose software to be used in this kind of device: dema-rc. Ultimate goal is to have a software …

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  2. git helper for “recursive rebase”

    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 …

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  3. Throw away” linux images in seconds

    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 …

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  4. Hacking the Intel fan, for fun

    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 …

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  5. Optimizing hash table with kmod as testbed

    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 …

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