Improve startup benchmark

Don't measure the time it takes to destruct the QQmlEngine, as that may
be heavy work due to the last sweep of the garbage collector heap and
deleting all engine-owned QObjects.

Change-Id: Ibdd3d92e306d0418ee7080077b8894950878ec43
Reviewed-by: Erik Verbruggen <erik.verbruggen@qt.io>

1 files changed, 15 insertions, 15 deletions

diff --git a/tests/benchmarks/startup/startup_bench.cpp b/tests/benchmarks/startup/startup_bench.cpp
index cdc754ec..9e734cf8 100644
--- a/tests/benchmarks/startup/startup_bench.cpp
+++ b/tests/benchmarks/startup/startup_bench.cpp
@@ -54,25 +54,21 @@
 #include <functional>
 #include <stdio.h>
 
-int runBenchmark(std::function<int()> f) {
+int runBenchmark(std::function<qint64()> f) {
     {
-        QElapsedTimer t;
-        t.start();
-        int r = f();
-        if (r == 0)
-            printf("%d,", static_cast<int>(t.elapsed()));
+        auto r = f();
+        if (r >= 0)
+            printf("%d,", static_cast<int>(r));
         else
-            return r;
+            return -1;
     }
 
     {
-        QElapsedTimer t;
-        t.start();
-        int r = f();
-        if (r == 0)
-            printf("%d\n", static_cast<int>(t.elapsed()));
+        auto r = f();
+        if (r >= 0)
+            printf("%d\n", static_cast<int>(r));
         else
-            return r;
+            return -1;
     }
 
     return 0;
@@ -83,14 +79,18 @@ int main(int argc, char *argv[])
 {
     QtQuickControlsApplication app(argc, argv);
 
-    auto startup = [&app]() {
+    auto startup = [&app]() -> qint64 {
+        QElapsedTimer timer;
+        timer.start();
         QQmlApplicationEngine engine(QUrl("qrc:/main.qml"));
         QObject::connect(&engine, &QQmlApplicationEngine::quit,
                          QCoreApplication::instance(), &QCoreApplication::quit);
         engine.load(QUrl("qrc:/timer.qml"));
         if (engine.rootObjects().size() != 2)
             return -1;
-        return app.exec();
+        if (app.exec() != 0)
+            return -1;
+        return timer.elapsed();
     };
 
     return runBenchmark(startup);