Hardware-based tick counters for high-precision benchmarks

• x86_64: executes RDTSC CPU instruction to read the time-stamp counter.
• AArch64: reads value of the CNTVCT_EL0 counter-timer register.

The breif description: https://sheroz.com/pages/blog/rust-hardware-based-tick-counters-for-high-precision-benchmarks.html

Tested on platforms

text x86_64 (Intel® Core™ i7) AArch64 (Apple M1 Pro)

Usage

For usage samples please look at src/bin/sample.rs

Basic usage

rust let start = tick_counter::start(); // ... lines of code to benchmark let elapsed_ticks = tick_counter::stop() - start; println!("Number of elapsed ticks: {}", elapsed_ticks);

Basic usage with helper

```rust use tick_counter::TickCounter;

let tickcounter = TickCounter::current(); // ... lines of code to benchmark let elapsedticks = tickcounter.elapsed(); println!("Number of elapsed ticks: {}", elapsedticks); ```

Extended usage

```rust println!("Environment: {}/{} {}", consts::OS, consts::FAMILY, consts::ARCH);

let (counterfrequency, accuracy) = tickcounter::frequency(); let frequencybase = match accuracy { tickcounter::TickCounterFrequencyBase::Hardware => "hardware provided".tostring(), tickcounter::TickCounterFrequencyBase::Measured(duration) => format!("software estimated in {:?}", duration) }; println!("Tick frequency, MHZ: {:.2} ({})", counterfrequency as f64 / 1e6f64, frequency_base);

let counteraccuracy = tickcounter::precisionnanoseconds(counterfrequency); println!("Tick accuracy, nanoseconds: {:.2}", counter_accuracy);

let counterstart = tickcounter::start(); thread::sleep(time::Duration::fromsecs(1)); let counterstop = tick_counter::stop();

println!("Tick counter start: {}", counterstart); println!("Tick counter stop: {}", counterstop);

let elapsedticks = counterstop - counterstart; println!("Elapsed ticks count in 1 seconds: {}", elapsedticks);

let elapsednanoseconds = (elapsedticks as f64) * counteraccuracy; println!("Elapsed nanoseconds according to elapsed ticks: {:.2}", elapsednanoseconds); ```

Outputs

1. Macbook Pro 16 2021 / Apple Silicon

text Apple M1 Pro MacOS Ventura 13.5.1, Darwin Kernel Version 22.6.0

Output

```text Basic usage: Number of elapsed ticks in 1s: 24120997

Basic usage with helper: Number of elapsed ticks in 1s: 24122097

Extended usage: Environment: macos/unix aarch64 Tick frequency, MHZ: 24.00 (hardware provided) Tick accuracy, nanoseconds: 41.67 Tick counter start: 103684134140 Tick counter stop: 103708255194 Elapsed ticks count in 1 seconds: 24121054 Elapsed nanoseconds according to elapsed ticks: 1005043916.67

Comparing the measurement methods using 100 samples: Elapsed time in nanoseconds, using std::time::Instant Mean = 60.34 Min = 41.00 Max = 167.00 Standard deviation = 23.92 (39.64 %) Elapsed time in nanoseconds, using tick_counter Mean = 42.41 Min = 42.00 Max = 83.00 Standard deviation = 4.08 (9.62 %) ```

2. Ubuntu 22.04 LTS / Intel® Core™ i7

text Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz Linux 6.2.0-31-generic #31~22.04.1-Ubuntu

Output

```text Basic usage: Number of elapsed ticks in 1s: 3430864159

Basic usage with helper: Number of elapsed ticks in 1s: 3430866807

Extended usage: Environment: linux/unix x86_64 Tick frequency, MHZ: 3430.87 (software estimated in 1s) Tick accuracy, nanoseconds: 0.29 Tick counter start: 14959335168548 Tick counter stop: 14962766085156 Elapsed ticks count in 1 seconds: 3430916608 Elapsed nanoseconds according to elapsed ticks: 1000013467.72

Comparing results, using 100 samples: Elapsed time in nanoseconds, using std::time::Instant Mean = 46.35 Min = 42.00 Max = 262.00 Standard deviation = 21.70 (46.82 %) Elapsed time in nanoseconds, using tick_counter Mean = 17.40 Min = 15.00 Max = 18.00 Standard deviation = 0.95 (5.45 %) ```