Viewing profile — lmb

Location: London, UK / Munich, Germany Remote: No, hybrid only Willing to relocate: Maybe Technologies: Go, C, eBPF, Linux Résumé/CV: on request Email: jobs@lmb.io Systems engineer…

Counter point from Gleixner which is worth reading for us in the peanut gallery: https://lwn.net/ml/linux-kernel/87r11qp63n.ffs@tglx/

Missing Allen (2001) by my late father Christian Bauer https://www.youtube.com/watch?v=kOXSI_vcqK8 Around the turn of the century, my dad's good friend and longtime collaborator Al…

We ended up with fasthash64 and lookup3 by looking for a fast hash that is easy to port to the restricted subset of C supported by eBPF with minimal changes. https://github.com/rur…

I think we tried siphash at some point, unfortunately it's significantly slower than the two hash functions we ended up using.

Count min sketches are really neat. A colleague at my old company used them to implement DDoS mitigations in eBPF and wrote it up: https://blog.cloudflare.com/building-rakelimit/ T…

We don't use kernel bypass anymore, it's all XDP: https://blog.cloudflare.com/l4drop-xdp-ebpf-based-ddos-mitig...

What does tail latency for the Zig pool look like? It seems like any Task that ends up in one of the overflow queues will stay there until at some ring buffer is emptied. Put anoth…

What does tooling / debugging for p4 look like? How do you inspect what happens inside a p4 dataplane? Context: I work on a L4 load balancer written in ebpf / XDP. Debugging that i…

There is a fair bit of co-evolution of the Linux BPF verifier and the BPF llvm backend. This means that the verifier is biased to do well on bytecode that is commonly emitted by cl…

Seems like the right move from a volunteer run project, what will the future will hold though? Artificial scarcity is always a problem. On another note, for just 20k$ I can offer y…

You're arguing that the majority of people use the term differently than you and are therefore wrong. Sounds like the definition of technobabble to me.

Total shot in the dark: I had a similar problem, it turned out the power supply for the router was faulty.

Can you define ready? The functionality of the library is solid, it's based on code we're using in production. We've not committed to a stable API however. (I'm one of the maintain…

In some of the code snippets, the following is used: threshold = -bound % bound I don't understand how that isn't always zero. What am I missing?

The problem is that different kernel configurations end up changing the layout of important data structures. Basically, you need to change the offsets that the eBPF uses. There is …

It doesn't give any specifics. "2 of 121 parameters were configured incorrectly". Maybe host and port? ;)

What do you mean with this? Refuse ANY is now a proposed RFC https://datatracker.ietf.org/doc/rfc8482/ How is that a band aid?

We've been using LMDB at Cloudflare to store small-ish configuration data, it has been rock solid. Thank you and the rest of the contributors for such a great library.

LMDB is not a great fit for something like the WAL, where new data is written at the end, and old data discarded at the start. It leads to fragmentation (especially if WAL entries …

Can you give an idea how big your cluster is? 10, 10s, 100s? I'm curious how well Normand works in reality, but it's hard to find ppl running it.

The byte code is used as a target for verification, and is designed to be easily JITable on x86 and arm. There are network cards which offer eBPF offload, but they only implement a…

A colleague of mine did a performance deep dive as well: https://blog.cloudflare.com/arm-takes-wing/ It's sad to see Qualcomm ditch such a good platform.

Ok, I've looked at the code, and based on that I think what I said in my original post is correct. GLB is more complex, but will maintain connections in more circumstances.