today's leftovers

posted by Roy Schestowitz on Dec 12, 2023

• APNIC ☛ Measurement and analysis of protocols at IETF 118

  Measuring QUIC (performance, spin bit, and ECN), transparent forwarders, and invalid prefix dropping.

• Andy Wingo: a simple hdr histogram

  Let’s assume that you decide on the histogram approach. How should you compute the bins? It would be nice to have microsecond accuracy on the small end, but if you bin by microsecond you could end up having millions of bins, which is not what you want. On the other end you might have multi-second GC pauses, and you definitely want to be able to record those values.

  Consider, though, that it’s not so important to have microsecond precision for a 2-second pause. This points in a direction of wanting bins that are relatively close to each other, but whose absolute separation can vary depending on whether we are measuring microseconds or milliseconds. You want approximately uniform precision over a high dynamic range.

  logarithmic binning

  The basic observation is that you should be able to make a histogram that gives you, say, 3 significant figures on measured values. Such a histogram would count anything between 1230 and 1240 in the same bin, and similarly for 12300 and 12400. The gap between bins increases as the number of digits grows.

  Of course computers prefer base-2 numbers over base-10, so let’s do that. Say we are measuring nanoseconds, and the maximum number of seconds we expect is 100 or so. There are about 2³⁰ nanoseconds in a second, and 100 is a little less than 2⁷, so that gives us a range of 37 bits. Let’s say we want a precision of 4 significant base-2 digits, or 4 bits; then we will have one set of 2⁴ bins for 10-bit values, another for 11-bit values, and so-on, for a total of 37 × 2⁴ bins, or 592 bins. If we use a 32-bit integer count per bin, such a histogram would be 2.5kB or so, which I think is acceptable.

  Say you go to compute the bin for a value. Firstly, note that there are some values that do not have 4 significant bits: if you record a measurement of 1 nanosecond, presumably that is just 1 significant figure. These are like the denormals in floating-point numbers. Let’s just say that recording a value val in [0, 2⁴-1] goes to bin val.

  If val is 2⁴ or more, then we compute the major and minor components. The major component is the number of bits needed to represent val, minus the 4 precision bits.

• Freexian Collaborators: Debian Contributions: Python 3.12 preparations, debian-printing, merged-/usr tranisition updates, and more! (by Utkarsh Gupta)

  Stefano uploaded a few packages in preparation for Python 3.12, including pycxx and cython. Cython has a major new version (Cython 3), adding support for 3.12, but also bringing changes that many packages in Debian aren’t ready to build with, yet. Stefano uploaded it to Debian experimental and did an archive rebuild of affected packages, and some analysis of the result. Matthias Klose has since filed bugs for all of these issues.

  This month Thorsten invested some of the previously obtained money to build his own printlab. At the moment it only consists of a dedicated computer with an USB printer attached. Due to its 64GB RAM and an SSD, building of debian-printing packages is much faster now. Over time other printers will be added and understanding bugs should be a lot easier now.

  Also Thorsten again adopted two packages, namely mink and ink, and moved them to the debian-printing team.

• IBM

  • Red Hat Official ☛ 2023-12-06 [Older] Red Hat Academy milestone: Empowering 50,000 students in 2023

  • Red Hat Official ☛ 2023-12-06 [Older] Secondary network overlays for virtualization workloads

• TLS and sign-on systems

  • University of Toronto ☛ 2023-12-09 [Older] A possible path to reliable name constraints on internal TLS CAs

  • University of Toronto ☛ 2023-12-08 [Older] Mapping out my understanding of (web-based) single sign-on systems

• Open Hardware/Modding

  • CNX Software ☛ Raspberry Pi releases PCIe FFC connector specifications, new HAT+ standard

    Raspberry Pi has released two new specifications one for the PCIe FFC connector and related cable and the other for the new Raspberry Pi HAT+ (HAT Plus) standard that’s simpler, takes into account new features in Raspberry Pi 4/5, and has fewer rules around mechanical dimensions.

  • CNX Software ☛ RoomSense IQ – An ESP32-S3 modular room monitor with mmWave radar presence detection (Crowdfunding)

    RoomSense IQ is a modular room monitor for presence-based home automation based on the ESP32-S3 module with Bluetooth Wi-Fi connectivity. It uses physical presence detection to automate your smart home devices. It comes with multiple sensors that can be used to detect human activity and track ambient light, temperature, and humidity levels. It uses mmWave radar technology to determine when rooms are empty and when they are occupied.

• K Desktop Environment/KDE SC/Qt

  • Scarlett Gately Moore: KDE: KDE Snaps 23.08.4, PIM! KDE neon, Debian

    This weeks big accomplishment is KDE PIM snaps! I have successfully added akonadi as a service via an akonadi content snap and running it as a service. Kaddressbook is our first PIM snap with this setup and it works flawlessly! It is available in the snap store. I have a pile of MRs awaiting approvals, so keep your eye out for the rest of PIM in the next day.

    KDE Applications 23.08.4 has been released and available in the snap store.

• Applications

  • Dedoimedo ☛ Sumatra PDF - Speed, elegance, efficiency

    Less is more. Behold, a review of Sumatra, a free, portable, open-source, and very small PDF reader, covering file format support, view modes, annotations, command palette, advanced options, and more. Have fun.