# Performance engineering, profilers, and seeing the invisible

DevFeed: [Performance engineering, profilers, and seeing the invisible](<https://devfeed.tech/articles/performance-engineering-profilers-and-seeing-the-invisible-21957.md>)

Original publisher: [Read original article](<https://blog.nelhage.com/post/profilers-seeing-the-invisible/>)

Author: Nelson Elhage

Published: 2023-12-18T16:00:00Z

Content type: opinion

Language: en

Sources: [Nelson Elhage](<https://devfeed.tech/sources/nelson-elhage.md>)

Topics: [Software](<https://devfeed.tech/topics/software.md>), [Tool](<https://devfeed.tech/topics/tool.md>), [coding](<https://devfeed.tech/topics/coding.md>)

Tags: [engineering](<https://devfeed.tech/tags/engineering.md>), [paper](<https://devfeed.tech/tags/paper.md>), [performance](<https://devfeed.tech/tags/performance.md>), [performance-engineering](<https://devfeed.tech/tags/performance-engineering.md>), [software](<https://devfeed.tech/tags/software.md>), [tools](<https://devfeed.tech/tags/tools.md>)

## AI overview

The article examines performance engineering through the idea that experts can perceive information absent from direct observation. It argues that profilers show where a particular program execution spends time, but effective optimization also requires understanding context and information not present in the profile.

## Source excerpt

I was recently introduced to the paper "Seeing the Invisible: Perceptual-Cognitive Aspects of Expertise" by Gary Klein and Robert Hoffman. It's excellent and I recommend you read it when you have a chance. Klein and Hoffman discuss the ability of experts to "see what is not there": in addition to observing data and cues that are present in the environment, experts perceive implications of these cues, such as the absence of expected or "typical" information, the typicality or atypicality of observed data, and likely/possible past and future time trajectories of a system based on a point-in-time snapshot or limited duration of observation.