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Comment by alexchamberlain | Hacker News Reader

According to Wikipedia, BPF stands for [Berkeley Packet Filter][1] and can be used to observe packets sent by a process.

[1]: https://en.m.wikipedia.org/wiki/Berkeley_Packet_Filter

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Technically, yes, but in practice not really; eBPF started as an extension of the packet filtering framework and then got generalized to be a nearly-universal debugging/monitoring/tracing system that's only sometimes used for packets. https://ebpf.io/ is a decent starting point for reading.

Thanks for explaining that - I was totally missing the point to be honest.

Yeah, the name is kinda unfortunate in the modern context, but in fairness it's easy to not expect that a packet filtering framework will turn out to be the basis for a universal kernel tracing system...

My biggest pet peeve is when authors don't just start with a 1-2 sentence outline of the topic that they're discussing, and instead go directly into acronym soup. And I've been in software development for a long time and have never heard of BPF/eBPF before.

Thank you for your explanation.

Brendan Gregg is the author of eBPF, and he writes on his blog. It is fair to assume a basic knowledge of his works when reading his website.

Maybe I’m misunderstanding what you mean by “author“, but BPF was invented by Steven McCanne, and Van Jacobson in 1992[0], and tweaked over the years by various developers and operating systems. It looks[1] like the Linux eBPF work was initiated by Alexei Starovoitov, and came to be exposed to users c. 2014.

[0] https://en.wikipedia.org/wiki/Berkeley_Packet_Filter

[1] https://lwn.net/Articles/740157/

Brendan Gregg is the author of most of the utilities, not bpf/ebpf itself. You can find a non-exhaustive list here: http://www.brendangregg.com/ebpf.html

I get that, and appreciate he’s productive and sharing his skill. I wasn’t sure though if the long history of other people’s hard work wasn’t being swept up in appreciation for ‘brendangregg

Thanks; I also summarize the history of eBPF in my BPF Performance Tools book (which I had checked by Alexei & Dan) and list the main contributors in the Acknowledgements page, as well as include them in talks (e.g. https://www.slideshare.net/brendangregg/bpf-internals-ebpf/1...). I do try hard to thank all involved. :-)

Modern BPF (eBPF) was created by Alexei Starovoitov and Daniel Borkmann, who are still maintainers but are joined by over a hundred contributors. I've spent most of my time contributing to the observability frontends, bcc and bpftrace. Apart from the people, the major companies contributing include Facebook and Isovalent; Microsoft are becoming its own major contributor to its own Windows implementation.

>Microsoft are becoming its own major contributor to its own Windows implementation.

Wait, what now !?

After checking : he wasn't joking[0]. Good job MS.

[0]:https://github.com/microsoft/ebpf-for-windows

I'm sorry, this indeed isn't correct. I cannot modify my comment for some reason now.

Brendan Gregg literally wrote the book on this kind of stuff, if you search for any of this tracing stuff it comes up with his website anyway.

Sorry, I just added a link to https://ebpf.io. Although I suspect that will also annoy people as it doesn't explain the BPF acronym: The reason is that we're now treating BPF as a technology name (like LLVM) and not an acronym, as the historical acronym (Berkeley Packet Filter) is plain confusing.

I think the real problem is that BPF was built by engineers without professional marketing help, who would have come up with a better name!

Thank you!

He did link to something, but for me that link was broken (https://brendangregg.com/blog/2021-07-03/BPF)

That's more because you're coming into an established site with an established topic that's been discussed for years. It doesn't really make sense to introduce every topic from scratch every time, because the assumption after a while is that the people reading have at least some prior knowledge or at least an interest in looking up what they don't know because they're there for a reason.

In other words, not every site is designed around link aggregators like HN, and some things will be assumed, just as if you open a book to some random chapter.

For me, BPF is the most exciting development in the kernel world for ages.

Brendan Gregg, the author of the posted blog entry, works with BPF on observability at Netflix and delivered a keynote at UbuntuMasters 2019. The video is on his blog is a great intro. [0]

I've been watching BPF for a couple of years now, and it seems slow on the uptake, but I hope Gregg is right that people will eventually start writing new drivers, firewalls, observability and security tools, loaded from userspace, but all running safely in a kernel vm, maybe even written in new async-first programming languages.

[0] https://brendangregg.com/blog/2019-12-02/bpf-a-new-type-of-s...

And eBPF stands for extended Berkeley Packet Filter:

> eBPF is an extended BPF JIT virtual machine in the Linux kernel

It's really quite an amazing tool, especially since you can use it to run sandboxed programs in kernel without changing kernel source or loading a kernel module. These programs can be written using a limited dialect of C.

Some examples of its use can be found here: https://github.com/iovisor/bcc/tree/master/examples

eBPF is more capable of BPF. It's a general hooking mechanism in the Linux kernel. Think Aspect-Oriented Programming, but in the kernel. The biggest benefit I think is that it can intercept and modify function calls in many places, not just the kernel. Intercepting/filtering bad data at the network driver level is much more efficient than letting the data reaching the kernel code.

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