Performance improvement for the Dart VM runtime method

runtime/vm/benchmark_test.cc

Index: runtime/vm/benchmark_test.cc
===================================================================
--- runtime/vm/benchmark_test.cc	(revision 11476)
+++ runtime/vm/benchmark_test.cc	(working copy)
@@ -200,6 +200,113 @@
 
 
 //
+// Measure time accessing internal and external strings.
+//
+static void DartStringAccess(Dart_NativeArguments args) {
+  Dart_EnterScope();
+  int count = Dart_GetNativeArgumentCount(args);
+  EXPECT_EQ(2, count);
+
+  // Get interations parameter.
+  Dart_Handle param1 = Dart_GetNativeArgument(args, 1);
+  EXPECT_VALID(param1);
+  EXPECT(Dart_IsInteger(param1));
+  bool fits = false;
+  Dart_Handle result = Dart_IntegerFitsIntoInt64(param1, &fits);
+  EXPECT_VALID(result);
+  EXPECT(fits);
+  int64_t iterations;
+  result = Dart_IntegerToInt64(param1, &iterations);
+  EXPECT_VALID(result);
+  EXPECT_LE(0, iterations);
+  EXPECT_LE(iterations, 10000000);
+
+  // Create strings.
+  uint8_t data8[] = { 'o', 'n', 'e', 0xFF };
+  int external_peer_data = 123;
+  Dart_Handle external_string = Dart_NewExternalString8(data8,
+                                                        ARRAY_SIZE(data8),
+                                                        &external_peer_data,
+                                                        NULL);
+  Dart_Handle internal_string = Dart_NewString("two");
+
+  // Run benchmark.
+  for (int64_t i = 0; i < iterations; i++) {

[Ivan Posva, 2012/08/28 22:21:20]

Since this is essentially the benchmark you can drop all of the surrounding
machinery (creating scripts, native functions, Dart invocations) and run this
loop directly.

+    EXPECT(Dart_IsString(internal_string));
+    EXPECT(Dart_IsString8(internal_string));
+    EXPECT(Dart_IsString16(internal_string));
+    EXPECT(!Dart_IsExternalString(internal_string));
+    EXPECT_VALID(external_string);
+    EXPECT(Dart_IsExternalString(external_string));
+    void* external_peer = NULL;
+    // 80% of benchmark is spent in the following call.
+    EXPECT_VALID(Dart_ExternalStringGetPeer(external_string, &external_peer));
+    EXPECT_EQ(&external_peer_data, external_peer);
+  }
+
+  Dart_ExitScope();
+}
+
+
+static Dart_NativeFunction bm_dsa_lookup(Dart_Handle name, int argument_count) {
+  const char* cstr = NULL;
+  Dart_Handle result = Dart_StringToCString(name, &cstr);
+  EXPECT_VALID(result);
+  if (strcmp(cstr, "init") == 0) {
+    return InitNativeFields;
+  } else {
+    return DartStringAccess;
+  }
+}
+
+
+BENCHMARK(DartStringAccess) {
+  const int kNumIterations = 10000000;
+  const char* kScriptChars =
+      "class Class extends NativeFieldsWrapper{\n"
+      "  int init() native 'init';\n"
+      "  int method(int param1) native 'method';\n"
+      "}\n"
+      "\n"
+      "void benchmark(int count) {\n"
+      "  Class c = new Class();\n"
+      "  c.method(count);\n"
+      "}\n";
+
+  Dart_Handle lib = TestCase::LoadTestScript(
+      kScriptChars,
+      reinterpret_cast<Dart_NativeEntryResolver>(bm_dsa_lookup));
+
+  // Create a native wrapper class with native fields.
+  Dart_Handle result = Dart_CreateNativeWrapperClass(
+      lib,
+      Dart_NewString("NativeFieldsWrapper"),
+      1);
+  EXPECT_VALID(result);
+
+  Dart_Handle args[1];
+  args[0] = Dart_NewInteger(kNumIterations);
+
+  // Warmup first to avoid compilation jitters.
+  result = Dart_Invoke(lib,
+                       Dart_NewString("benchmark"),
+                       1,
+                       args);
+  EXPECT_VALID(result);
+
+  Timer timer(true, "DartStringAccess benchmark");
+  timer.Start();
+  Dart_Invoke(lib,
+              Dart_NewString("benchmark"),
+              1,
+              args);
+  timer.Stop();
+  int64_t elapsed_time = timer.TotalElapsedTime();
+  benchmark->set_score(elapsed_time);
+}
+
+
+//
 // Measure compile of all dart2js(compiler) functions.
 //
 static char* ComputeDart2JSPath(const char* arg) {