rtla timerlat: Debugging Real-Time Linux Scheduling Latency
summary
rtla timerlat is a kernel+userspace tool that measures and traces scheduling latency, decomposes spikes into irq, RQ and thread components, and produces a standardized auto-analysis stops at >30 µs / >50 µs examples that points to the root cause (e.g., irq disabled in cgroup or a compress_pages worker). It uses the OS-noise tracer and histograms, supports kernel or user-thread measurement, detects hardware/hypervisor pauses, and adds only ~1–2 µs tracing overhead while proving actionable fingerprints.
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chapters (17)
- 0:00rtla timerlat introduction
- 1:03Real-time Linux motivations
- 3:30Black-box latency limits
- 5:38timerlat tool architecture
- 7:47Demo of timerlat top
- 11:06Auto-analysis for debugging
- 13:38Real-time scheduling abstractions
- 15:05Latency spike case study
- 19:04Continuous tracing benefits
- 20:51Jitter beyond OS scope
- 22:14Thread latency in non-RT kernel
- 24:44Advanced timerlat tracing
- 27:19Histograms for statistics
- 34:07User space workload analysis
- 36:34Hardware noise measurement
- 38:22Final remarks and future
- 40:13Q&A on hypervisor noise
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