LTTng for full stack tracing

on YouTube ↗26m

" summary

Full-stack tracing using LTTng plus Qt user-space trace points and a CTF→Chrome trace converter identifies exact causes of slow startup: kernel sched switches, syscalls, plugin loads and mmap activity show that disk-heavy debug logging and loading unneeded image plugins — on an NVIDIA Tegra X1 Yocto build — cause multi-second delays; raising I/O priority and stripping plugins drops startup from ~5s to ~1s. Built a tracegen for Qt tracepoints and a CTF-to-JSON pipeline, records 20s full-system traces ~10–218 MB binary (~2 MB JSON) with negligible overhead.

AI-written summary · about

" chapters (11)

1. 0:00Introduction to full-stack tracing
2. 2:11Motivating real-world example
3. 7:57Why LTTng for tracing
4. 9:43Setting up LTTng on device
5. 11:10Recording a system trace
6. 14:28Analyzing trace data
7. 17:00CTF2: Custom trace visualization
8. 20:15Key trace points explained
9. 22:45Future of tracing in Qt
10. 23:45Performance impact and overhead
11. 24:53Q&A and conclusion

" related talks

• 37mKernel and userspace tracing with LTTng and friendsSuchakrapani Datt · FUDCon Pune 2015
• 36mLTTNG-UST Efficient System Wide User-Space TracingChristian Babeux · Collaboration Summit 2013
• 48mEfficient and Large-scale Infrastructure Monitoring With TracingJulien Desfossez · LinuxCon + CloudOpen Europe 2013
• 35mLinux Tracing updatesMr Masami Hiramatsu · Linux Plumbers Conference 2025
• 38mLTTng: Beyond Ring-Buffer Based TracingJérémie Galarneau · LinuxCon Europe 2022
• 12mStriaTrace: Efficient Tracing and Diagnosis for Online LLM InferenceEnnan Zhai, Erci Xu, Jingren Zhou, Kun Qian, Xue Li, Wenyuan Yu, Guangtao Xue, Yanqing Chen, Haonan Wu, Jingbo Xu · 20th USENIX Symposium on Operating Systems Design and Implementation (OSDI '26)
• 05mPerformance analysis using SystraceCarmen Jackson · Android Dev Summit 2018
• 25mDebugging Slow Infrastructure Runs With OpenTelemetry in OpenTofuJames Humphries · OpenTofu Day Europe 2026