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From Milliseconds to Microseconds: Tuning Go for Extreme Performance
Advanced Go Performance Tuning: Speed Up Your Applications by Minimizing Latency and Maximizing Throughput
It started with a question during a production incident review: “Why did this request take 4 milliseconds when it should’ve taken less than one?” Most would shrug — 4 milliseconds isn’t terrible. But for us, working on an ultra-low-latency service powering real-time trading decisions, every microsecond counted.
I work in a performance-obsessed team. We measure latency in microseconds. When Go was chosen as the language for our internal high-frequency messaging router, we knew we had the right tool. But even Go, with all its simplicity and power, doesn’t make microsecond performance easy out of the box.
Through performance profiling, CPU tuning, memory analysis, and concurrency design, we brought the latency down from ~4ms to sub-300µs in our most critical paths. This article is a story of how we did that — with code, lessons, and battle scars from the forums and flamegraphs.
The Bottlenecks Aren’t Always Where You Think
The initial implementation was simple and idiomatic: REST handlers, database calls, some JSON decoding…
