rdtsc

Description

The most high resolution timing in NodeJs

This module provide cross platform function rdtsc().

rdtsc() return counts the number of cycles since computer start

If you run in on Windows it will call C++ function __rdtsc() that call processor command RDTSC (Read Time Stamp Counter)

(rdtsc() - rdtsc()) is always < 0

Notice: you should not use parallel threads since you calc performance

Install

npm i rdtsc -S

Features

RDTSC

var { rdtsc } = require('rdtsc')
console.log(rdtsc()) // 3864063236708616 cycles
console.log(rdtsc() - rdtsc()) // -2971 cycles, minimum = -130 cycles

Calc Performance

Accuracy: +/- 4 cycles

Syntax

/*

calcPerformance(testTimeMilliseconds, ...funcs)

result = {
    calcInfo: { 
        iterationCycles: 413.22476287663505,
        iterations: 5622917,
        funcsCount: 3,
        testTime: 1000 // milliseconds
    },
    cycles: [ 54n, 54n, 55n ], // is BigInt
    absoluteDiff: [ 0, 0 ], // cycles[i] - cycles[0]
    relativeDiff: undefined, // absoluteDiff[i] / absoluteDiff[0]
}

*/

Examples

const { calcPerformance } = require('rdtsc')

calcPerformance(1000, () => {}, () => {}, () => {})

/*
result = {
    calcInfo: { 
        iterationCycles: 413.22476287663505,
        iterations: 5622917,
        funcsCount: 3,
        testTime: 1000 // milliseconds
    },
    cycles: [ 54n, 54n, 54n ],
    absoluteDiff: [ 0, 0 ],
    relativeDiff: undefined,
}

OR

result = {
    ...
    cycles: [ 54n, 55n, 54n ],
    absoluteDiff: [ 1, 0 ],
    relativeDiff: [ 0 ],
}

OR

result = {
    ...
    cycles: [ 54n, 58n, 52n ],
    absoluteDiff: [ 4, -2 ],
    relativeDiff: [ -0.5 ],
}
*/

calcPerformance(1000, () => {}, () => {})

/*
result = {
    ...
    cycles: [ 54n, 54n ],
    absoluteDiff: [ 0 ],
    relativeDiff: undefined,
}
*/

calcPerformance(1000, () => {})

/*
result = {
    ...
    cycles: [ 54n ],
    absoluteDiff: undefined,
    relativeDiff: undefined,
}
*/

var { calcPerformance } = require('rdtsc')

var result = calcPerformance(
    1000,
    () => {

    },
    () => {
        Object.keys(Math)
    }
)

console.log('"Object.keys(Math)" min cycles =', result.absoluteDiff[0]) // about 20-40 cycles

Thread Priority

Implemented only for Windows platform

Examples

const { runInRealtimePriority, getThreadPriority, getProcessPriority } = require('rdtsc')

runInRealtimePriority(() => {
    console.log('getThreadPriority = ', getThreadPriority()) // === THREAD_PRIORITY_REALTIME
    console.log('getProcessPriority = ', getProcessPriority()) // === PROCESS_PRIORITY_REALTIME
})

const { setThreadPriority, getThreadPriority, isWin, THREAD_PRIORITY_REALTIME } = require('rdtsc')

if (isWin) {
    console.log(getThreadPriority()) // === THREAD_PRIORITY_NORMAL
} else {
    console.log(getThreadPriority()) // === undefined
}

var previousPriority = setThreadPriority(THREAD_PRIORITY_REALTIME)

try {
    // <your code>
} finally {
    setThreadPriority(previousPriority)
}

Priorities list

/*

const THREAD_PRIORITY_IDLE = -15
const THREAD_PRIORITY_LOWEST = -2
const THREAD_PRIORITY_BELOW_NORMAL = -1
const THREAD_PRIORITY_NORMAL = 0
const THREAD_PRIORITY_ABOVE_NORMAL = 1
const THREAD_PRIORITY_HIGHEST = 2
const THREAD_PRIORITY_REALTIME = 15 // THREAD_PRIORITY_REALTIME

*/

Process Priority

Implemented only for Windows platform

Example

const { setProcessPriority, getProcessPriority, isWin, PROCESS_PRIORITY_REALTIME } = require('rdtsc')

if (isWin) {
    console.log(getProcessPriority()) // === PROCESS_PRIORITY_NORMAL
} else {
    console.log(getProcessPriority()) // === undefined
}

var previousPriority = setProcessPriority(PROCESS_PRIORITY_REALTIME)

try {
    // <your code>
} finally {
    setProcessPriority(previousPriority)
}

Priorities list

/*

const PROCESS_PRIORITY_IDLE = 0x00000040 // IDLE_PRIORITY_CLASS
const PROCESS_PRIORITY_BELOW_NORMAL = 0x00004000 // BELOW_NORMAL_PRIORITY_CLASS
const PROCESS_PRIORITY_NORMAL = 0x00000020 // NORMAL_PRIORITY_CLASS
const PROCESS_PRIORITY_ABOVE_NORMAL = 0x00008000 // ABOVE_NORMAL_PRIORITY_CLASS
const PROCESS_PRIORITY_HIGHEST = 0x00000080 // HIGH_PRIORITY_CLASS
const PROCESS_PRIORITY_REALTIME = 0x00000100 // REALTIME_PRIORITY_CLASS

*/

License

Unlimited Free