rdtsc
v3.0.4
Published
The most high resolution cross platform timing in NodeJs that use processor command RDTSC. Calculate performance with accuracy +/- 4 processor cycles.
Downloads
183
Maintainers
Readme
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
*/