feat(xsnap): high resolution timer: performance.now()

packages/xsnap/src/xsnap.c

@@ -59,6 +59,7 @@ static void fx_gc(xsMachine* the);
 // static void fx_isPromiseJobQueueEmpty(xsMachine* the);
 static void fx_markTimer(txMachine* the, void* it, txMarkRoot markRoot);
 static void fx_print(xsMachine* the);
+static void fx_performance_now(xsMachine* the);
 static void fx_setImmediate(txMachine* the);
 // static void fx_setInterval(txMachine* the);
 // static void fx_setTimeout(txMachine* the);
@@ -80,13 +81,14 @@ static char* fxWriteNetStringError(int code);
 // The order of the callbacks materially affects how they are introduced to
 // code that runs from a snapshot, so must be consistent in the face of
 // upgrade.
-#define mxSnapshotCallbackCount 5
+#define mxSnapshotCallbackCount 6
 txCallback gxSnapshotCallbacks[mxSnapshotCallbackCount] = {
 	fx_issueCommand, // 0
 	fx_Array_prototype_meter, // 1
 	fx_print, // 2
 	fx_setImmediate, // 3
 	fx_gc, // 4
+	fx_performance_now, // 5
 	// fx_evalScript,
 	// fx_isPromiseJobQueueEmpty,
 	// fx_setInterval,
@@ -552,6 +554,12 @@ void fxBuildAgent(xsMachine* the)
 	// slot = fxNextHostFunctionProperty(the, slot, fx_setInterval, 1, xsID("setInterval"), XS_DONT_ENUM_FLAG);
 	// slot = fxNextHostFunctionProperty(the, slot, fx_setTimeout, 1, xsID("setTimeout"), XS_DONT_ENUM_FLAG);
 
+	mxPush(mxObjectPrototype);
+	txSlot* performance = fxLastProperty(the, fxNewObjectInstance(the));
+	fxNextHostFunctionProperty(the, performance, fx_performance_now, 1, xsID("now"), XS_DONT_ENUM_FLAG);
+	slot = fxNextSlotProperty(the, slot, the->stack, xsID("performance"), XS_DONT_ENUM_FLAG);
+	mxPop();
+
 	// mxPush(mxObjectPrototype);
 	// fxNextHostFunctionProperty(the, fxLastProperty(the, fxNewObjectInstance(the)), fx_print, 1, xsID("log"), XS_DONT_ENUM_FLAG);
 	// slot = fxNextSlotProperty(the, slot, the->stack, xsID("console"), XS_DONT_ENUM_FLAG);
@@ -1526,6 +1534,14 @@ void fxFreeSlots(txMachine* the, void* theSlots)
 	c_free(theSlots);
 }
 
+void fx_performance_now(txMachine *the)
+{
+	c_timeval tv;
+	c_gettimeofday(&tv, NULL);
+	mxResult->kind = XS_NUMBER_KIND;
+	mxResult->value.number = (double)(tv.tv_sec * 1000.0) + ((double)(tv.tv_usec) / 1000.0);
+}
+
 
 // Local Variables:
 // tab-width: 4

packages/xsnap/test/test-xs-perf.js

@@ -0,0 +1,56 @@
+// eslint-disable-next-line import/no-extraneous-dependencies
+import test from 'ava';
+import { xsnap } from '../src/xsnap';
+import { options } from './test-xsnap';
+
+test('meter details', async t => {
+  const opts = options();
+  const vat = xsnap(opts);
+  t.teardown(() => vat.terminate());
+  const result = await vat.evaluate(`
+  let m = new Map();
+  let s1 = new Set();
+  for (ix = 0; ix < 20000; ix++) {
+    m.set(ix, 'garbage');
+    s1.add(ix);
+  }
+  for (ix = 0; ix < 20000; ix++) {
+    m.delete(ix);
+    s1.delete(ix);
+  }
+  `);
+  const {
+    meterUsage: { meterType, ...meters },
+  } = result;
+  t.log(meters);
+  const { entries, fromEntries } = Object;
+  t.deepEqual(
+    {
+      compute: 'number',
+      allocate: 'number',
+      allocateChunksCalls: 'number',
+      allocateSlotsCalls: 'number',
+      garbageCollectionCount: 'number',
+      mapSetAddCount: 'number',
+      mapSetRemoveCount: 'number',
+      maxBucketSize: 'number',
+    },
+    fromEntries(entries(meters).map(([p, v]) => [p, typeof v])),
+  );
+  t.is(meterType, 'xs-meter-6');
+});
+
+test('high resolution timer', async t => {
+  const opts = options();
+  const vat = xsnap(opts);
+  t.teardown(() => vat.terminate());
+  await vat.evaluate(`
+      const send = it => issueCommand(ArrayBuffer.fromString(JSON.stringify(it)));
+
+      const t = performance.now();
+      send(t);
+    `);
+  const [milliseconds] = opts.messages.map(JSON.parse);
+  t.log({ milliseconds, date: new Date(milliseconds) });
+  t.is('number', typeof milliseconds);
+});

packages/xsnap/test/test-xsnap.js

@@ -19,7 +19,7 @@ const xsnapOptions = {
   stdout: 'inherit',
 };
 
-function options() {
+export function options() {
   const messages = [];
   async function handleCommand(message) {
     messages.push(decoder.decode(message));
@@ -505,40 +505,3 @@ test('property name space exhaustion: orderly fail-stop', async t => {
     });
   }
 })();
-
-test('meter details', async t => {
-  const opts = options();
-  const vat = xsnap(opts);
-  t.teardown(() => vat.terminate());
-  const result = await vat.evaluate(`
-  let m = new Map();
-  let s1 = new Set();
-  for (ix = 0; ix < 20000; ix++) {
-    m.set(ix, 'garbage');
-    s1.add(ix);
-  }
-  for (ix = 0; ix < 20000; ix++) {
-    m.delete(ix);
-    s1.delete(ix);
-  }
-  `);
-  const {
-    meterUsage: { meterType, ...meters },
-  } = result;
-  t.log(meters);
-  const { entries, fromEntries } = Object;
-  t.deepEqual(
-    {
-      compute: 'number',
-      allocate: 'number',
-      allocateChunksCalls: 'number',
-      allocateSlotsCalls: 'number',
-      garbageCollectionCount: 'number',
-      mapSetAddCount: 'number',
-      mapSetRemoveCount: 'number',
-      maxBucketSize: 'number',
-    },
-    fromEntries(entries(meters).map(([p, v]) => [p, typeof v])),
-  );
-  t.is(meterType, 'xs-meter-6');
-});