My name is Toke Høiland-Jørgensen. I’m a Linux kernel developer at Red Hat, where I work on the upstream kernel networking stack with a focus on XDP. I maintain xdp-tools, as well as the sch_cake qdisc and the ath9k WiFi driver in the kernel. I completed my PhD in November 2018 at Karlstad University in Sweden, after which I moved back to Denmark.

I have been involved in the bufferbloat project for several years, and apart from my kernel work, I am also the author of the Flent performance measurement tool and the sqm-scripts QoS configuration tool for OpenWrt. I also occasionally write other code, most of which I collect on Github.

When I’m not sitting in front of a computer, I like reading books, playing music (I’m a fairly mediocre drummer) and dancing Lindy Hop. I am also the “father” of Marvin, the world’s most adorable Rhodesian Ridgeback.

Talks

Reverse chronological order. Sadly I’ve been terrible at keeping this up to date, so it is reconstructed after the fact and probably has some holes in it.

• “The Benefits of Open - for Research and Source Code”. Keynote, 18th Swedish National Computer Networking and Cloud Computing Workshop (SNCNW 2023), June 2023. Slides.

• “Achieving lower latency with eBPF and XDP”. Understanding Latency webinar, Online, March 2023. Slides. Video.

• “It’s the latency, stupid!” Driving IT, Copenhagen, Denmark, November 2022. Slides. Video.

• “eBPF: Safely observe and extend your operating system”. DeiC conference, Kolding, Denmark, October 2022. Slides

• “The Promise of eBPF for the Edge”. eBPF Summit, Online, September 2022. Slides. Video.

• “Bringing packet queueing to XDP”. Linux Plumbers Conference, Dublin, Ireland, September 2022. Slides. Video.

• “XDP + BPF_PROG_TEST_RUN = A programmable traffic generator!” Lund Linux Con, Lund, Sweden, April 2022. Slides

• “Klar til, at internettet forsvinder på grund af krigen i cyberspace? Analogiseringsstyrelsen er!“. Podcast episode (as an interview subject, in Danish), Online, March 2022. Episode.

• “Multiple XDP programs on a single interface - status and next steps”. Linux Plumbers conference, Online, August 2020. Slides. Video

• “Bufferbloat and Beyond: How we reduced delays in the Linux networking stack by orders of magnitude”. Bornhack, Denmark, August 2019. Slides. Video.

• “XDP feature planning” and “friendlier UAPI for XDP_REDIRECT”. Linux Kernel Developers’ Netconf 2019, Boston, USA, June 2019. Slides 1. Slides 2.

• “Bufferbloat mitigation in the Linux WiFi stack – status and ongoing work”. Lund Linux Con, Lund, Sweden, May 2019. Slides.

• “PoliFi: Airtime Policy Enforcement for WiFi”. IEEE WCNC ‘19, Marrakech, Morocco, Apr 2019. Slides.

• “XDP hands-on tutorial”. With Jesper Brouer. NetDev 0x13, Prague, Czech Republic, Mar 2019. Slides. Video.

• “The eXpress Data Path: Fast Programmable Packet Processing in the Operating System Kernel”. ACM CoNEXT ‘18, Heraklion, Greece, Dec 2018. Slides.

• “Bufferbloat and Beyond: Removing Performance Barriers in Real-world Networks”. Thesis defence, Karlstad, Sweden, Nov 2018. Slides. Video.

• “XDP - challenges and future work”. With Jesper Brouer. LPC Networking Track, Vancouver, Canada, Nov 2018. Slides.

• “Update on the Bird implementation status of Babel”. IETF 101, London, UK, Mar 2018. Slides. Video

• “Flent: The Flexible Network Tester”. ValueTools, Venice, Italy, Dec 2017. Slides.

Publications

Reverse chronological order.

• Sundberg, S., Brunstrom, A., Ferlin-Reiter, S., Høiland-Jørgensen, T., Brouer, J.D. Efficient Continuous Latency Monitoring with eBPF. Passive and Active Measurement, PAM 2023.

• C. A. Grazia, N. Patriciello, T. Høiland-Jørgensen, M. Klapez and M. Casoni, Aggregating Without Bloating: Hard Times for TCP on Wi-Fi in IEEE/ACM Transactions on Networking, vol. 30, no. 5, Oct. 2022.

• T. Høiland-Jørgensen et al. PoliFi: Airtime Policy Enforcement for WiFi, IEEE WCNC ‘19, Marrakech, Morocco, April 2019.

• T. Høiland-Jørgensen et al. The eXpress Data Path: Fast Programmable Packet Processing in the Operating System Kernel, ACM CoNEXT ‘18, Heraklion, Greece, December 2018.

• T. Høiland-Jørgensen. Bufferbloat and Beyond: Removing Performance Barriers in Real-World Networks, PhD thesis, Karlstad University, November 2018. Full PDF (8MB).

• T. Høiland-Jørgensen. Analysing the Latency of Sparse Flows in the FQ-CoDel Queue Management Algorithm, IEEE Communications Letters, Volume 22, Issue 11, November 2018.

• Carlo Augusto Grazia et al. Adapting TCP Small Queues for IEEE 802.11 Networks, IEEE PIMRC 2018, Bologna, Italy, September 2018.

• T. Høiland-Jørgensen et al. Piece of CAKE: A Comprehensive Queue Management Solution for Home Gateways, IEEE LANMAN, Washington DC, June 2018.

• T. Høiland-Jørgensen et al. The Flow Queue CoDel Packet Scheduler and Active Queue Management Algorithm, RFC 8290, January 2018.

• T. Høiland-Jørgensen et al. Flent: The FLExible Network Tester, ValueTools 2017, Venice, Italy, December 2017.

• T. Høiland-Jørgensen et al. Ending the Anomaly: Achieving Low Latency and Airtime Fairness in WiFi. USENIX ATC ‘17, Santa Clara, CA, USA, July 2017.

• T. Høiland-Jørgensen. On The Bleeding Edge: Debloating Internet Access Networks, Licentiate Thesis, Karlstad University, 2016.

• T. Høiland-Jørgensen et al. Measuring Latency Variation in the Internet. ACM CoNEXT ‘16, Irvine, CA, USA, December 2016.

• T. Høiland-Jørgensen et al. The Good, the Bad and the WiFi: Modern AQMs in a Residential Setting, Computer Networks (2015).

• T. Høiland-Jørgensen. Flent: The FLExible Network Tester, SNCNW ‘15.

License

Content on this blog is licensed under the CC BY-SA 4.0 license. Code is licensed under the GNU GPLv3.