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eBPF Instruction Sets
Not everyone who develops BPF programs knows that several versions of the instruction set exist. This isn’t really surprising given documentation on the subject is scarce. So let’s go through the different eBPF instruction sets, why they exist, and why their choice matters.
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Features of bpftool: the thread of tips and examples to work with eBPF objects
Working with eBPF? Discover how bpftool can help you load, inspect, update your eBPF programs, maps, and more.
Read moreHow To Add eBPF Observability To Your Product
There's an arms race to add eBPF to commercial observability products, and in this post I'll describe how to quickly do that. This is also applicable for people adding it to their own in-house monitoring systems.
Read moreBPF tips & tricks: the guide to bpf_trace_printk() and bpf_printk()
Any non-trivial BPF program always needs some amount of debugging to get it working correctly. Unfortunately, there isn't a BPF debugger yet, so the next best thing is to sprinkle printf()-like statements around and see what's going on in the BPF program. BPF equivalent of printf() is the bpf_trace_printk() helper. In this blog post we'll look at how to use it, what are its limitations, and how to work around them.
Read moreeBPF Updates #5: CNCF Proposals, Kinvolk Acquired, eCHO, the Cost of Tail Calls, Systemd Features, Reverse Debugging, Static Linking
Spring is back in the Northern Hemisphere, and with it all kinds of features are blooming for eBPF. Kernel 5.12 is out and version 5.13 is on track to bring new exciting functionalities. At the same time, new projects hatch and companies are enjoying renewed activity. Several eBPF-related projects applied to join or upgrade their status in the bosom of CNCF. After some delay, no doubt caused by winter hibernation, welcome to the fifth issue of the eBPF Updates!
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BMC: Accelerating Memcached using Safe In-kernel Caching and Pre-stack Processing
Tomorrow, Yoann Ghigoff et al. will present their paper BMC: Accelerating Memcached using Safe In-kernel Caching and Pre-stack Processing at NSDI 2021. In this paper, the authors propose to speed up Memcached using eBPF by implementing a transparent, first-level cache at the XDP hook. It’s not everyday we see BPF being used on application protocols!
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The Cost of BPF Tail Calls
For an upcoming blog post, I wanted to measure the cost of BPF tail calls. Tail calls allow you to jump from one BPF program to another. Their overhead varied a lot in recent kernels, with a first increase caused by Spectre mitigations and a decrease thanks to improvements in Linux 5.5.
Read moreeBPF Updates #4: In-Memory Loads Detection, Debugging QUIC, Local CI Runs, MTU Checks, but No Pancakes
In several parts of the globe, February is traditionally about love, and pancakes. eBPF sure received a lot of love over the last weeks! Blogging, conferencing, and kernel development have resumed full speed after the quiet period at the end of the year. Here are all the latest updates, plus a section focusing on program size limits. Alas, uncertainty remains as for eBPF getting pancakes.
Read moreeBPF Updates #3: Atomics Operations, Socket Options Retrieval, Syscall Tracing Benchmarks, eBPF in the Supply Chain
With the festive season, it would seem that eBPF blogging has cooled down a little, and we have fewer items to report this time. But eBPF is getting traction everywhere, so we can be confident that more material will be available for the months to come. Let's wager that 2021 will be full of new features, tutorials, deep dives, commercial news, and good surprises in general. In the meantime, here are all the latest news. Welcome to the third issue of the eBPF Updates, and Happy New Year!
Read moreeBPF Updates #2: eBPF with Zig, libbpf-bootstrap, Rust Linker, BTF in Kernel Modules, Cgroup-Based Memory Accounting
Welcome to the second issue of the _eBPF Updates_! This time we have interesting resources about how to write eBPF programs with Zig, or with Rust, or on how to manage them with libbpf. On the kernel side, modules now support BTF, and improvements to memory accounting for eBPF should help to solve the limitations of rlimit. Did this just sound incomprehensible to you? Do not fear, we also have some gentle introductions to eBPF in the list. This issue also introduces a “Did You Know” section, and this time the focus is on CO-RE. Read, learn, trace, and filter!
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