Sha256: 4ad8bbd046fa3a38a03be0c56b5d79298ba57169cbdcd63395eaef92dbc8eeeb
Contents?: true
Size: 1.39 KB
Versions: 22
Compression:
Stored size: 1.39 KB
Contents
"use strict";
const { hrtime } = require("./utils");
// The HR-TIME spec calls for 5-μs accuracy. Check that we have that in both hrtime() and Date.now().
function testClockAccuracy() {
// Test hrtime() first. The check is simpler and more stable, and we use hrtime() to measure Date.now()'s performance.
const roundTrip = hrtime(hrtime());
if (roundTrip[0] > 1 || roundTrip[1] > 5e3 * 2) {
return false;
}
// Test Date.now() twice: first with a looser bound (10 μs) but with a smaller run time to filter out very bad
// Date.now() performance, and then with a tighter bound (5 μs) to check we have the accuracy we need.
let times;
// eslint-disable-next-line no-unused-vars
let cur;
let start;
let end;
times = 100;
start = hrtime();
while (times-- > 0) {
cur = Date.now();
}
end = hrtime(start);
if ((end[0] * 1e9 + end[1]) > 1000000) {
return false;
}
times = 10000;
start = hrtime();
while (times-- > 0) {
cur = Date.now();
}
end = hrtime(start);
if ((end[0] * 1e9 + end[1]) > 50000000) {
return false;
}
return true;
}
// Warm up the function.
testClockAccuracy();
testClockAccuracy();
testClockAccuracy();
const TIMES = 5;
const THRESHOLD = 0.6 * TIMES;
let accurates = 0;
for (let i = 0; i < TIMES; i++) {
if (testClockAccuracy()) {
accurates++;
}
}
const isAccurate = accurates >= THRESHOLD;
module.exports = isAccurate;
Version data entries
22 entries across 22 versions & 2 rubygems