https://github.com/fast/fastant

A drop-in replacement for std::time::Instant that is faster and more accurate.
https://github.com/fast/fastant

instant rust rust-lang time

Last synced: about 1 year ago
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A drop-in replacement for std::time::Instant that is faster and more accurate.

• Host: GitHub
• URL: https://github.com/fast/fastant
• Owner: fast
• License: apache-2.0
• Created: 2024-08-12T13:46:49.000Z (almost 2 years ago)
• Default Branch: main
• Last Pushed: 2025-02-13T09:09:49.000Z (over 1 year ago)
• Last Synced: 2025-04-06T03:12:52.429Z (about 1 year ago)
• Topics: instant, rust, rust-lang, time
• Language: Rust
• Homepage: https://crates.io/crates/fastant
• Size: 252 KB
• Stars: 23
• Watchers: 0
• Forks: 2
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Fastant

A drop-in replacement for [`std::time::Instant`](https://doc.rust-lang.org/std/time/struct.Instant.html) that measures time with high performance and high accuracy powered by [Time Stamp Counter (TSC)](https://en.wikipedia.org/wiki/Time_Stamp_Counter).

[![Actions Status](https://github.com/fast/fastant/workflows/CI/badge.svg)](https://github.com/fast/fastant/actions)

[![Documentation](https://docs.rs/fastant/badge.svg)](https://docs.rs/fastant/)

[![Crates.io](https://img.shields.io/crates/v/fastant.svg)](https://crates.io/crates/fastant)

[![LICENSE](https://img.shields.io/github/license/fast/fastant.svg)](LICENSE)

## Usage

```toml

[dependencies]

fastant = "0.1"

```

```rust

fn main() {

    let start = fastant::Instant::now();

    let duration: std::time::Duration = start.elapsed();

}

```

## Motivation

This library is used by a high performance tracing library [`fastrace`](https://github.com/fast/fastrace). The main purpose is to use [Time Stamp Counter (TSC)](https://en.wikipedia.org/wiki/Time_Stamp_Counter) on x86 processors to measure time at high speed without losing much accuracy.

## Platform Support

Currently, only the Linux on `x86` or `x86_64` is backed by Time Stamp Counter (TSC). On other platforms, Fastant falls back to `std::time`. If TSC is unstable, it will also fall back to `std::time`.

If speed is privileged over accuracy when fallback occurs, you can use `fallback-coarse` feature to use coarse time:

```toml

[dependencies]

fastant = { version = "0.1", features = ["fallback-coarse"] }

```