perf-map-agent
parca-agent
perf-map-agent | parca-agent | |
---|---|---|
3 | 10 | |
1,622 | 480 | |
1.0% | 4.2% | |
10.0 | 9.9 | |
over 3 years ago | 6 days ago | |
C | Go | |
GNU General Public License v3.0 only | 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.
perf-map-agent
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Launch perf-map-agent with executable instead of pid
Is there a way to launch perf-map-agent's script perf-java-flames with a process executable instead of first launching the executable and then monitoring it's pid? By monitoring the pid, I think we are skipping some of the scripts launched at startup.
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Wazero: The zero dependency WebAssembly runtime for Go developers
I don't know enough about wasm runtimes, but for example JIT runtimes like nodejs (or JVM via perf-map-agent [0]) allow writing out debug infos via the Linux Kernel JIT-Interface [1], which debuggers and profilers can then pick up to symbolize stack traces.
[0] https://github.com/jvm-profiling-tools/perf-map-agent
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Fantastic Symbols and Where to Find Them - Part 2
The runtimes usually don't enable providing symbol mappings by default. You might need to change a configuration, run the virtual machine with a specific flag/environment variable or run an additional program to obtain these mappings. For example, JVM needs an agent to provide supplemental symbol mapping files, called perf-map-agent.
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?
rbspy - Sampling CPU profiler for Ruby
kubectl-flame - Kubectl plugin for effortless profiling on kubernetes
wapc-go - Golang-based WebAssembly Host Runtime for waPC-compliant modules
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.
karmem - Karmem is a fast binary serialization format, faster than Google Flatbuffers and optimized for TinyGo and WASM.
pwru - Packet, where are you? -- eBPF-based Linux kernel networking debugger
otto - A JavaScript interpreter in Go (golang)
go-profiler-notes - felixge's notes on the various go profiling methods that are available.
profefe - Continuous profiling for long-term postmortem analysis
lisa - Linux Integrated System Analysis
parca-demo - A collection of languages and frameworks profiled by Parca and Parca agent