Why Traditional Latency Measurement Tools Provide Misleading Results
By
dempedempe
Kettled twice. Extra chewy, extra trustworthy.
Summary
The article critiques traditional latency measurement tools and methodologies, arguing they provide misleading results. Based on a workshop by Gil Tene (CTO of Azul Systems), it explains how common approaches like averages, percentiles, and histograms fail to capture the true nature of latency distributions, especially tail latency. The article advocates for better visualization tools like HDR histograms and coordinated omission correction to understand latency behavior accurately, particularly for high-performance systems where tail latency matters most.
Key quotes
· 5 pulledOkay, maybe not everything you know about latency is wrong. But now that I have your attention, we can talk about why the tools and methodologies you use to measure and reason about latency are likely horribly flawed.
In fact, they're not just flawed, they're probably lying to your face.
The problem with averages is that they hide the outliers, and with latency, the outliers are often what matter most.
Percentiles are better than averages, but they still don't tell the whole story about latency distributions.
Coordinated omission is the practice of measuring latency only when the system is ready to respond, which completely misses the worst-case scenarios.
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