Improve n-body bench env (AssemblyScript#457)

Author: MaxGraey

examples/n-body/README.md

@@ -31,17 +31,17 @@ Benchmark
 
 ***Environment:***
 - MacBook Pro (Retina, 15-inch, Late 2013)
-- macOS 10.14
-- node.js v10.11.0
-- rustc 1.31.0-nightly (4bd4e4130 2018-10-25)
+- macOS 10.14.3
+- node.js v11.9.0
+- rustc 1.33.0-nightly (ceb251214 2019-01-16)
 
 ***Results:***
 
 |        Target           |  Time, ***ms*** | Size, ***KB*** |
 |-------------------------|-----------------|----------------|
-| **AssemblyScript WASM** | **3167**        | **2**          |
-| AssemblyScript ASMJS    | 3633            | 21*            |
-| JavaScript              | 2628            | 5*             |
-| Rust WASM               | 3876            | 13             |
+| **AssemblyScript WASM** | **2901**        | **2**          |
+| AssemblyScript ASMJS    | 3720            | 19*            |
+| JavaScript              | 2716            | 5*             |
+| Rust WASM               | 2883            | 13             |
 
 ___* unminified___

examples/n-body/package.json

@@ -10,7 +10,7 @@
     "tsbuild": "tsc -p assembly -t ES2017 -m commonjs --outDir build",
     "build": "npm run asbuild && npm run tsbuild",
     "server": "http-server . -o -c-1",
-    "test": "node tests"
+    "test": "node --noliftoff --nowasm-tier-up --wasm-lazy-compilation --wasm-no-bounds-checks --expose-gc tests"
   },
   "devDependencies": {
     "http-server": "^0.11.1",

examples/n-body/tests/index.js

@@ -34,11 +34,25 @@ const nbodyJS = new Function(
   ...Object.keys(scopeJS).concat(src + "\nreturn exports"))(...Object.values(scopeJS)
 );
 
+function gcCollect() {
+  if (global.gc) {
+    global.gc();
+    global.gc();
+  }
+}
+
+function sleep(delay) {
+  var start = Date.now();
+  while (Date.now() < start + delay);
+}
+
 function test(nbody, steps) {
   nbody.init();
   var start = process.hrtime();
   nbody.bench(steps);
-  return process.hrtime(start);
+  let t = process.hrtime(start);
+  gcCollect();
+  return t;
 }
 
 var steps = process.argv.length > 2 ? parseInt(process.argv[2], 10) : 20000000;
@@ -66,6 +80,7 @@ prologue("Rust WASM", steps);
 epilogue(test(nbodyRS, steps));
 
 console.log("\nWARMED UP SERIES:\n");
+sleep(1000);
 
 prologue("AssemblyScript WASM", steps);
 epilogue(test(nbodyAS, steps));