April 26, 2026
When clocks go brrr, time goes huh?
The fastest Linux timestamps
Dev makes time 30% faster; commenters split: speed demons, safety cops, and ‘don’t trace it’
TLDR: A developer sped up Linux timestamps by 30% with a custom clock trick, but even they say most people shouldn’t use it. Comments split between “don’t trace 100‑ns stuff,” clever “do the math later” hacks, and warnings that time can appear to go backwards—speed versus sanity, in nanoseconds.
Linux dev speeds up timestamps by 30% by skipping the usual system path and reading the CPU’s built‑in counter, then calmly says: “almost nobody should do this.” The crowd? Not calm. The thread splits into three camps: the “go faster” crew, the safety marshals, and the pragmatists.
Speed fans cheer the hack and push it further. Veserv waves a clever trick: don’t convert raw counter ticks to time at all—“inject clock adjustments into your log stream” and do the math later to shave even more overhead. Pragmatists like jeffbee clap back: if an operation is 100 nanoseconds, don’t trace it—use a profiler when you actually need to look. Meanwhile, safety sirens blare as amluto warns that time can literally appear to go backwards between threads, fueling “we broke time” memes and jokes about Schrödinger’s stopwatch.
Others drop receipts: rockwotj links Abseil’s linear time-from-cycles hack, while RossBencina asks if ARM or RISC‑V have anything like this counter at all. The vibe: brilliant micro-optimization meets real-world gotchas. The author’s own warning—almost nobody should ship this—becomes the punchline, as the debate turns into speed versus sanity, and whether chasing nanoseconds is worth flirting with time travel.
Key Points
- •The article targets reducing timestamp overhead in an OpenTelemetry-based low-latency pipeline with a 50–100 ns per-span budget.
- •Naive back-to-back std::chrono calls to system_clock and steady_clock take about 46–49 ns on x86 Linux, consuming most of the budget.
- •Despite vDSO avoiding kernel context switches for clock_gettime(), measurable overhead remains that impacts ultra-low-latency tracing.
- •By understanding x86 TSC and vDSO internals, custom timers can bypass vDSO to maintain precision while improving performance.
- •Results indicate around a 30% speedup and over 50% reduction in timing overhead from the initial naive attempt; focus is on Linux 6.8, noting vDSO data page changes in 6.15.