pics
parca-agent
pics | parca-agent | |
---|---|---|
12 | 10 | |
10,313 | 484 | |
0.3% | 5.0% | |
7.4 | 9.9 | |
3 months ago | about 14 hours ago | |
Assembly | Go | |
- | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
pics
- Hello, PNG
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can’t be the only one
Using this framework, you can started with some excercises or dig into some file formats if you want something different (many file format have segments with variable length so the header will provide either offset or length which makes a good execercise for understanding pointer arithmetic).
- Binary Posters
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How to generate an object file (and later an exe) from assembly
And this is not official, but you'll probably like it: https://github.com/corkami/pics/tree/master/binary/pe101
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An MP4 file first draft
Author's github: https://github.com/corkami/pics
He works on things like hash collisions, image files that contain an image of their own hash, "polyglot" files and such like.
I think this is intended as a "minimum viable mp4 file" to show what the required binary parts are.
- Computing Posters
- ELF 101 a Linux Executable Walkthrough by Ange Albertini [pdf]
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Fantastic Symbols and Where to Find Them - Part 1
ELF Executable and Linkable Format diagram by Ange Albertini
parca-agent
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Flameshow: A Terminal Flamegraph Viewer
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
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How to troubleshoot memory leaks in Go with Grafana Pyroscope
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.
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Frame pointers vs. DWARF – my verdict
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.
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Dwarf-Based Stack Walking Using eBPF
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
- Parca Agent rewrites eBPF in-kernel C code in Rust (using Aya-rs)
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Fantastic Symbols and Where to Find Them - Part 2
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!
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Fantastic Symbols and Where to Find Them - Part 1
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.
What are some alternatives?
pdftilecut - pdftilecut lets you sub-divide a PDF page(s) into smaller pages so you can print them on small form printers.
kubectl-flame - Kubectl plugin for effortless profiling on kubernetes
Plex-Movie-Poster-Display - Scraps the Plex sessions page to display the current playing movie or TV show poster on a screen.
ebpf - ebpf-go is a pure-Go library to read, modify and load eBPF programs and attach them to various hooks in the Linux kernel.
MP4Inspector - A Chrome extension to help you inspect Mp4 video content and find irregularities in video streams.
perf-map-agent - A java agent to generate method mappings to use with the linux `perf` tool
GpxTrackPoster - Create a visually appealing poster from your GPX tracks
pwru - Packet, where are you? -- eBPF-based Linux kernel networking debugger
basis_universal - Basis Universal GPU Texture Codec
rbspy - Sampling CPU profiler for Ruby
book-mdpc - Il cinema tra le righe... di codice!
go-profiler-notes - felixge's notes on the various go profiling methods that are available.