Viewing profile — felixge

We had reached out to y'all last year to explore taking ideas from your format. It definitely looks interesting! But IIRC nobody from your team ended up making it to one of our SIG…

OTel Profiling SIG maintainer here: I understand your concern, but we’ve tried our best to make things efficient across the protocol and all involved components. Please let us know…

Do you think the GC roots alone (goroutine stacks with goroutine id, package globals) would be enough? I think in many cases you'd want the reference chains. The GC could certainly…

I'd love to hear more! What kind of profiling issues are you running into? I'm assuming the inuse memory profiles are sometimes not good enough to track down leaks since they only …

Hacking into the Go runtime with eBPF is definitely fun. But for a more long term solution in terms of reliability and overhead, it might be worth raising this as a feature request…

+1. In particular []byte slice allocations are often a significant driver of GC pace while also being relatively easy to optimize (e.g. via sync.Pool reuse).

This is great, thank you.

I'm skeptical that it's worth it myself, this was just a fun research project for me. But once hardware shadow stacks are available, I think this could be great. To answer your fir…

That seems to be windows only? My main target OS is Linux.

Thank you so much, this is very helpful and interesting. I'll try to experiment with this at some point.

Thanks for the reply! What does the API for accessing the shadow stack from user space look like? I didn't see anything for it in the kernel docs [1]. I agree about the need for sw…

I don't think any obvious 10%+ opportunities have been overlooked. Go is optimizing for fast and simple builds, which is a bit at odds with optimal code gen. So I think the biggest…

That's what hardware shadow stacks in modern intel/arm CPUs can do! It just needs to be exposed to user space and become widely available.

I know that at least two engineers from the runtime team have seen the post in the #darkarts channel of gopher slack. One of them left a fire emoji :). I'll probably bring it up in…

Thanks! And to answer you question: No, it won't speed up Go programs for now. This was mostly a fun research project for me. The low hanging fruits to speed up stack unwinding in …

OP here, happy to answer any question.

Thanks for the reply. I ended up implementing this idea in Go and wrote a blog post about the results: https://blog.felixge.de/blazingly-fast-shadow-stacks-for-go/ I'm curious if y…

Looking at the code [1] it seems like the library is actively trying to handle this problem. [1] https://github.com/koute/not-perf/blob/master/nwind/src/loca...

Dynamic patching of return addresses is a very cool trick. I don't think I've seen this before. Have you run into any situations where this crashes programs or otherwise interferes…