parca-agent VS textual-web

If that's true, you should probably update the docs. Everything I could find implied dotnet, jvm, python were still unsupported. For example, the roadmap section of the readme mentions most of these but nothing mentions dotnet. However I did find your tickets and a demo being merged in which makes it seem maybe supported?

Ticket: https://github.com/parca-dev/parca-agent/issues/161

Demo: https://github.com/parca-dev/parca-demo/pull/18

Couldn't see any advantages to this over https://github.com/parca-dev/parca-agent. Which uses eBPF so it can be used with non-instrumented apps and code paths.

The pervasive lack of frame pointers is the reason why we've developed a custom format derived from DWARF unwind information thanks to some insights: DWARF unwind information is incredible flexible, it supports many arches and allows restoring any arbitrary register. But we only need 3: the frame pointer, the stack pointer, and in non-x86 the return address.

In addition, this encoding doesn't use that many bytes, but unfortunately reading and parsing that information is quite expensive.

For that reason I've developed a new unwinder that uses custom unwind information derived from DWARF (https://www.polarsignals.com/blog/posts/2022/11/29/profiling..., previously discussed in https://news.ycombinator.com/item?id=33788794) that runs in BPF. This new compact representation can be binary searched easily and each unwind row has a size of 16 bytes. I are currently working on reducing it down to ~10 bytes.

All the code is fully OSS (Apache 2.0 for userspace and GPL for BPF), and part of the Parca project (https://github.com/parca-dev/parca-agent).

We've also given some talks in FOSDEM going deeper into how we made it scale for many big processes.

I find this surprising! Was this for off the shelf applications or some custom binaries?

As mentioned above, we see DWARF expressions such as `DW_CFA_def_cfa_expression` on the regular. See the "Test Plan" section and commit messages of the PR that introduced support for this particular opcode [0]

[0]: https://github.com/parca-dev/parca-agent/pull/1058

Let's see an example perf map file for NodeJS. The runtimes out there output this file with more or less the same format, more or less!

The good news is we got you covered. If you are using Parca Agent, we already do the heavy lifting for you to symbolize captured stack traces. And we keep extending our support for the different languages and runtimes.

The worst part is there's absolutely nothing stopping anyone for making the same principles work in the browser. Zero. Nada. It's trivially proven by compiling apps to wasm and running in a terminal emulator but there's nothing stopping anyone from building react-terminal-like or whatever except that... I don't even know what since we've got https://github.com/Textualize/textual-web.

People have thrown out decades of UX research and engineering out of the window because it isn't cool anymore. Makes me sick.

This is awesome work and textual being able to support terminal or web (https://github.com/Textualize/textual-web) also gives hope that this can be more than a terminal app. I'm hoping that in the future features like this can be standard in Linux's perf tool, for example, Firefox profiler support was recently added as a Google summer-of-code contribution: https://perf.wiki.kernel.org/index.php/Tutorial#Firefox_Prof...

It appears that, by default, the textual-web command makes a WebSocket connection to textualize-dev.io and hosts through that. Unlike regular HTTP which (usually) requires a server, WebSocket is a session-based network protocol that allows for long connections with bidirectional traffic.

Take a look at the repo, because the implementation’s fairly small and the README has more info: https://github.com/Textualize/textual-web