diff -r 000000000000 -r 6474c204b198 js/src/parjs-benchmarks/mandelbrot.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/parjs-benchmarks/mandelbrot.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,61 @@
+// Adapted from
+//
+// https://github.com/RiverTrail/RiverTrail/blob/master/examples/mandelbrot/mandelbrot.js
+//
+// which in turn is adapted from a WebCL implementation available at
+//
+// http://www.ibiblio.org/e-notes/webcl/mandelbrot.html
+
+var nc = 30, maxCol = nc*3, cr,cg,cb;
+
+load(libdir + "util.js");
+
+// this is the actual mandelbrot computation, ported to JavaScript
+// from the WebCL / OpenCL example at
+// http://www.ibiblio.org/e-notes/webcl/mandelbrot.html
+function computeSetByRow(x, y) {
+  var Cr = (x - 256) / scale + 0.407476;
+  var Ci = (y - 256) / scale + 0.234204;
+  var I = 0, R = 0, I2 = 0, R2 = 0;
+  var n = 0;
+  while ((R2+I2 < 2.0) && (n < 512)) {
+    I = (R+R)*I+Ci;
+    R = R2-I2+Cr;
+    R2 = R*R;
+    I2 = I*I;
+    n++;
+  }
+  return n;
+}
+
+function computeSequentially() {
+  result = [];
+  for (var r = 0; r < rows; r++) {
+    for (var c = 0; c < cols; c++) {
+      result.push(computeSetByRow(c, r));
+    }
+  }
+  return result;
+}
+
+function computeParallel() {
+  return new ParallelArray([rows, cols], function(r, c) {
+    return computeSetByRow(c, r);
+  }).flatten();
+}
+
+function compare(arrs, pas) {
+  for (var r = 0; r < rows; r++) {
+    for (var c = 0; c < cols; c++) {
+      assertEq(seq[c + r * cols], par.get(r, c));
+    }
+  }
+}
+
+var scale = 10000*300;
+var rows = 1024;
+var cols = 1024;
+
+// Experimentally, warmup doesn't seem to be necessary:
+benchmark("MANDELBROT", 1, DEFAULT_MEASURE,
+          computeSequentially, computeParallel);