--- title: "A Systems Engineer’s Guide to Benchmarking with RDTSC" url: https://daily.dev/posts/a-systems-engineer-s-guide-to-benchmarking-with-rdtsc-prrmz5wdd source_url: https://blog.codingconfessions.com/p/rdtsc type: article source: "Confessions of a Code Addict" published: 2025-10-23T11:38:31.061Z updated: 2026-03-15T03:29:04.244Z tags: ["hardware", "performance"] reading_time: 14 upvotes: 1 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # A Systems Engineer’s Guide to Benchmarking with RDTSC **[Confessions of a Code Addict](https://daily.dev/sources/codeconfessions)** · 14 min read · 1 upvotes · 0 comments ## Summary Learn how to use the x86 RDTSC instruction for precise cycle-level performance measurement. The guide explains the CPU's timestamp counter, challenges of out-of-order execution, and how to use serializing instructions (cpuid) and memory fences (lfence, sfence, mfence) to obtain accurate benchmarks. Includes practical code examples demonstrating proper RDTSC usage with rdtscp, handling core migration, and avoiding common pitfalls when measuring code that executes in hundreds of cycles. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [The fastest Linux timestamps · hmpc](https://daily.dev/posts/the-fastest-linux-timestamps-hmpc-evqoy4ob7) · Lobsters · 0 upvotes · 0 comments - [The Linux Kernel Ready To Make TSC A Hard Requirement For x86 CPUs](https://daily.dev/posts/the-linux-kernel-ready-to-make-tsc-a-hard-requirement-for-x86-cpus-yiexmkbe9) · Phoronix · 0 upvotes · 0 comments --- Tags: [#hardware](https://daily.dev/tags/hardware), [#performance](https://daily.dev/tags/performance) [View this post on daily.dev](https://daily.dev/posts/a-systems-engineer-s-guide-to-benchmarking-with-rdtsc-prrmz5wdd)