Benchmark: Quake InvertSqrt

Script Preparation code:

var i;
var r;
var v = 2**16;

function test1() {
  for(i=0; i < 1000; ++i) {
    r = Math.sqrt(v);
  }
}

function test2() {
  for(i=0; i < 1000; ++i) {
    r = Q_rsqrt(v) * v;
  }
}

const bytes = new ArrayBuffer(Float32Array.BYTES_PER_ELEMENT);
const floatView = new Float32Array(bytes);
const intView = new Uint32Array(bytes);
const threehalfs = 1.5;

function Q_rsqrt(number) {
  const x2 = number * 0.5;
  floatView[0] = number;
  intView[0] = 0x5f3759df - ( intView[0] >> 1 );
  let y = floatView[0];
  y = y * ( threehalfs - ( x2 * y * y ) );

  return y;
}

Tests:

Math.sqrt
test1()
Quake InvertSqrt
test2()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Math.sqrt
Quake InvertSqrt

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 4 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36 OPR/104.0.0.0

Browser/OS: Opera 104 on Windows

View result in a separate tab

Test name	Executions per second
Math.sqrt	5214.8 Ops/sec
Quake InvertSqrt	4657.9 Ops/sec

Quake InvertSqrt (version: 0)

Comparing performance of: Math.sqrt vs Quake InvertSqrt

Created: 5 years ago by: Guest

Jump to the latest result

Math.sqrt

Quake InvertSqrt

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A