NikolayMakhonin
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)](https://en.wikipedia.org/wiki/TimeStamp_Counter)
(rdtsc() - rdtsc()) is always < 0
Notice: you should not use parallel threads since you calc performance
Install
npm i rdtsc -SFeatures
RDTSC
var { rdtsc } = require('rdtsc')
console.log(rdtsc()) // 3864063236708616 cycles
console.log(rdtsc() - rdtsc()) // -2971 cycles, minimum = -130 cyclesCalc 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 cyclesThread 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
*/