Matrix multiplication with asm.js

JavaScript performance comparison

Revision 3 of this test case created by Alexander Gessler

Info

Trying super-fast matrix multiplication with asm.js by using a huge pool of matrices exclusively used as asm.js heap. User code indexes matrices by their position in that pool.

github.com/acgessler Matrix mult code from Brandon Jones's Gl-matrix

Preparation code

 
<script>
Benchmark.prototype.setup = function() {
    // trying super-fast matrix multiplication with asm.js by using a huge pool
    // of matrices exclusively used as asm.js heap. User code indexes matrices
    // by their position in that pool.
   
    // Alexander Gessler, 2013 (github.com/acgessler)
   
    var COUNT = 100;
    var elements = 16 * COUNT;
   
    var matrixpool = new Float32Array((Math.ceil(elements / 1024.0) * 1024) | 0); // multiple of 4096 bytes
    console.log('mpool: ' + matrixpool.length);
   
    function mat_mod(stdlib, foreign, heap) {
      "use asm";
   
      var m = new stdlib.Float32Array(heap);
   
      function multiply(idx_a, idx_b, idx_dest) {
        idx_a = idx_a | 0;
        idx_b = idx_b | 0;
        idx_dest = idx_dest | 0;
   
        idx_a = idx_a << 4;
        idx_b = idx_b << 4;
        idx_dest = idx_dest << 4;
   
        for (var i = 0 | 0; i < 4; i = (i + 1) | 0) {
          for (var j = 0 | 0; j < 4; j = (j + 1) | 0) {
            var c = +0.0;
            for (var k = 0 | 0; k < 4; k = (k + 1) | 0) {
              c = +(c + m[(idx_a + (i << 2) + k) | 0] * m[(idx_b + (k << 2) + j) | 0]);
            }
            m[(idx_dest + 4 * i + j) | 0] = c;
          }
        }
      }
   
      return {
        multiply: multiply
      }
    }
   
    var mod = mat_mod(window, undefined, matrixpool);
   
   
    // fill all matrices with values
    for (var i = matrixpool - 1; i >= 0; --i) {
      matrixpool[i] = i % 2 ? 0.5 : 2.0;
    }
};
</script>

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Testing in unknown unknown
Test Ops/sec
matrix multiplication
// multiply lots of matrices
for (var k = 0; k < 5; ++k) {
  for (var i = 0; i < COUNT; ++i) {
    for (var j = COUNT - 1; j >= 0; --j) {
      mod.multiply(i, j, (i + j) % COUNT);
    }
  }
}
pending…
same as before
// multiply lots of matrices
for (var k = 0; k < 5; ++k) {
  for (var i = 0; i < COUNT; ++i) {
    for (var j = COUNT - 1; j >= 0; --j) {
      mod.multiply(i, j, (i + j) % COUNT);
    }
  }
}
pending…

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