cheat.sh/latency: Visualizing System Performance for Developers

When Pavel Piatruk created cheat.sh/latency, he didn't just build another developer tool—he created a visual shorthand for understanding system performance that has become essential for programmers worldwide.

The tool, accessible via curl cheat.sh/latency, presents a text-based visualization of latency numbers that every developer should understand. It transforms abstract performance metrics into something tangible, showing how long operations take relative to each other through ASCII art boxes.

The visualization covers critical aspects of modern computing:

• Memory operations: L1 cache reference (1ns), L2 cache reference (4ns), main memory (100ns)
• Storage performance: SSD random read (16.0us), SSD sequential read (5ns), disk seek (1.6ms)
• Network latency: same datacenter round trip (500us), commodity network (100ns), transatlantic (150ms)
• CPU operations: branch mispredict (3ns), mutex lock/unlock (16ns)
• Data processing: compressing 1KB with Snappy (12.245us)

What makes cheat.sh/latency particularly valuable is its accessibility. Unlike complex profiling tools that require setup and interpretation, this visualization provides immediate context. When developers consider optimizing a piece of code, they can quickly reference these numbers to understand whether their optimization efforts are likely to yield meaningful improvements.

The tool builds on the famous "Jeff Dean's latency numbers" that have circulated in the software development community for years. While those numbers provided a useful reference, cheat.sh/latency makes them interactive and visually intuitive.

"In the world of performance optimization, understanding relative performance is more important than absolute numbers," explains Colin Scott, whose interactive latencies visualization inspired this text-based version. "This tool helps developers internalize these relationships in a way that sticks."

The tool is part of the larger cheat.sh project, a comprehensive cheat sheet service that provides quick references for over 50 programming languages. The latency visualization has become one of its most popular features, demonstrating developers' hunger for practical performance knowledge.

Unlike many developer tools that attempt to gamify or oversimplify performance concepts, cheat.sh/latency respects the complexity of system performance while making it approachable. It doesn't promise to solve all performance problems, but it provides the foundational knowledge needed to ask the right questions.

For developers working on performance-critical applications, from high-frequency trading systems to web backends, this simple visualization offers an immediate reality check. When considering whether to optimize a database query, implement a caching layer, or restructure algorithmic code, these numbers provide context for decision-making.

The tool's MIT license and open-source nature have contributed to its widespread adoption. It's not backed by venture capital or a marketing team—its spread through the developer community is organic, based purely on its utility.

In an era where performance optimization is often overshadowed by feature development, cheat.sh/latency serves as a reminder that understanding system fundamentals remains essential for building efficient software. The visualization doesn't just show numbers—it helps developers internalize the cost of different operations, making them better equipped to write performant code.

For developers who want to explore further, the source code is available on GitHub, where Piatruk continues to refine and expand the visualization based on community feedback.