From 48f19e43c5ceeed6b8f714fc921566f9260c78db Mon Sep 17 00:00:00 2001
From: Alexey Ushakov <avu@openjdk.org>
Date: Wed, 1 Jun 2022 09:48:15 +0000
Subject: [PATCH] 8287453: RenderPerfTest incorrectly measures performance

Reviewed-by: prr
---
 .../client/RenderPerfTest/Makefile            |  15 +-
 .../client/RenderPerfTest/build.xml           |   3 +-
 .../src/renderperf/RenderPerfLCDTest.java     | 373 ------------------
 .../src/renderperf/RenderPerfTest.java        | 129 +++---
 4 files changed, 76 insertions(+), 444 deletions(-)
 delete mode 100644 test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfLCDTest.java

diff --git a/test/jdk/performance/client/RenderPerfTest/Makefile b/test/jdk/performance/client/RenderPerfTest/Makefile
index 4dbbe9197f2c8..eca1c976d9405 100644
--- a/test/jdk/performance/client/RenderPerfTest/Makefile
+++ b/test/jdk/performance/client/RenderPerfTest/Makefile
@@ -1,5 +1,6 @@
 #
-# Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2022, JetBrains s.r.o.. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -28,13 +29,11 @@ DIST=dist
 RESOURCES=resources
 
 RENDERPERF_CLASSES = $(CLASSES)/renderperf/RenderPerfTest.class
-RENDERPERFLCD_CLASSES = $(CLASSES)/renderperf/RenderPerfLCDTest.class
 RENDERPERF_SOURCES = $(SOURCEPATH)/renderperf/RenderPerfTest.java
-RENDERPERFLCD_SOURCES = $(SOURCEPATH)/renderperf/RenderPerfLCDTest.java
 
 RENDERPERF_RESOURCES = $(CLASSES)/renderperf/images/duke.png
 
-all: mkdirs $(DIST)/RenderPerfTest.jar $(DIST)/RenderPerfLCDTest.jar
+all: mkdirs $(DIST)/RenderPerfTest.jar
 
 run: mkdirs $(DIST)/RenderPerfTest.jar
 	java -jar $(DIST)/RenderPerfTest.jar
@@ -44,11 +43,6 @@ $(DIST)/RenderPerfTest.jar: \
 	$(CLASSES)/renderperf.manifest
 	jar cvmf $(CLASSES)/renderperf.manifest $(DIST)/RenderPerfTest.jar -C $(CLASSES) .
 
-$(DIST)/RenderPerfLCDTest.jar: \
-	$(RENDERPERFLCD_CLASSES) $(RENDERPERFLCD_RESOURCES) \
-	$(CLASSES)/renderperflcd.manifest
-	jar cvmf $(CLASSES)/renderperflcd.manifest $(DIST)/RenderPerfLCDTest.jar -C $(CLASSES) .
-
 $(CLASSES)/renderperf/images/%: $(RESOURCES)/renderperf/images/%
 	cp -r $< $@
 
@@ -56,9 +50,6 @@ $(CLASSES)/renderperf/images/%: $(RESOURCES)/renderperf/images/%
 $(CLASSES)/renderperf.manifest:
 	echo "Main-Class: renderperf.RenderPerfTest" > $@
 
-$(CLASSES)/renderperflcd.manifest:
-	echo "Main-Class: renderperf.RenderPerfLCDTest" > $@
-
 $(DIST):
 	mkdir  $(DIST)
 
diff --git a/test/jdk/performance/client/RenderPerfTest/build.xml b/test/jdk/performance/client/RenderPerfTest/build.xml
index 0aebb7ca70085..aa20830c322c6 100644
--- a/test/jdk/performance/client/RenderPerfTest/build.xml
+++ b/test/jdk/performance/client/RenderPerfTest/build.xml
@@ -1,5 +1,6 @@
 <!--
- Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ Copyright (c) 2019, 2022, Oracle and/or its affiliates. All rights reserved.
+ Copyright (c) 2022, JetBrains s.r.o.. All rights reserved.
  DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 
  This code is free software; you can redistribute it and/or modify it
diff --git a/test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfLCDTest.java b/test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfLCDTest.java
deleted file mode 100644
index abe5cc37b6e02..0000000000000
--- a/test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfLCDTest.java
+++ /dev/null
@@ -1,373 +0,0 @@
-/*
- * Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-package renderperf;
-
-import java.awt.Color;
-import java.awt.Dimension;
-import java.awt.Frame;
-import java.awt.Graphics;
-import java.awt.Graphics2D;
-import java.awt.RenderingHints;
-import java.awt.Robot;
-
-import java.awt.event.WindowAdapter;
-import java.awt.event.WindowEvent;
-import java.awt.geom.AffineTransform;
-import java.awt.geom.Point2D;
-import java.awt.geom.QuadCurve2D;
-import java.awt.image.BufferedImage;
-import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-import java.util.HashSet;
-import java.util.Objects;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.atomic.AtomicBoolean;
-
-import javax.imageio.ImageIO;
-import javax.swing.JPanel;
-import javax.swing.SwingUtilities;
-import javax.swing.Timer;
-
-public class RenderPerfLCDTest {
-    private static HashSet<String> ignoredTests = new HashSet<>();
-
-    private final static int N = 1000;
-    private final static float WIDTH = 800;
-    private final static float HEIGHT = 800;
-    private final static float R = 25;
-    private final static int BW = 50;
-    private final static int BH = 50;
-    private final static int COUNT = 300;
-    private final static int DELAY = 10;
-    private final static int RESOLUTION = 5;
-    private final static int COLOR_TOLERANCE = 10;
-    private final static int MAX_MEASURE_TIME = 5000;
-
-
-    interface Configurable {
-        void configure(Graphics2D g2d);
-    }
-
-    interface Renderable {
-        void setup(Graphics2D g2d);
-        void render(Graphics2D g2d);
-        void update();
-    }
-
-    static class Particles {
-        private float[] bx;
-        private float[] by;
-        private float[] vx;
-        private float[] vy;
-        private float r;
-        private int n;
-
-        private float x0;
-        private float y0;
-        private float width;
-        private float height;
-
-        Particles(int n, float r, float x0, float y0, float width, float height) {
-            bx = new float[n];
-            by = new float[n];
-            vx = new float[n];
-            vy = new float[n];
-            this.n = n;
-            this.r = r;
-            this.x0 = x0;
-            this.y0 = y0;
-            this.width = width;
-            this.height = height;
-            for (int i = 0; i < n; i++) {
-                bx[i] = (float) (x0 + r + 0.1 + Math.random() * (width - 2 * r - 0.2 - x0));
-                by[i] = (float) (y0 + r + 0.1 + Math.random() * (height - 2 * r - 0.2 - y0));
-                vx[i] = 0.1f * (float) (Math.random() * 2 * r - r);
-                vy[i] = 0.1f * (float) (Math.random() * 2 * r - r);
-            }
-
-        }
-
-        void render(Graphics2D g2d, ParticleRenderer renderer) {
-            for (int i = 0; i < n; i++) {
-                renderer.render(g2d, i, bx, by, vx, vy);
-            }
-        }
-
-        void update() {
-            for (int i = 0; i < n; i++) {
-                bx[i] += vx[i];
-                if (bx[i] + r > width || bx[i] - r < x0) vx[i] = -vx[i];
-                by[i] += vy[i];
-                if (by[i] + r > height || by[i] - r < y0) vy[i] = -vy[i];
-            }
-
-        }
-
-    }
-
-    ParticleRenderable createPR(ParticleRenderer renderer) {
-        return new ParticleRenderable(renderer);
-    }
-
-    static class ParticleRenderable implements Renderable {
-        ParticleRenderer renderer;
-        Configurable configure;
-
-        ParticleRenderable(ParticleRenderer renderer, Configurable configure) {
-            this.renderer = renderer;
-            this.configure = configure;
-        }
-
-        ParticleRenderable(ParticleRenderer renderer) {
-            this(renderer, null);
-        }
-
-        @Override
-        public void setup(Graphics2D g2d) {
-            if (configure != null) configure.configure(g2d);
-        }
-
-        @Override
-        public void render(Graphics2D g2d) {
-            balls.render(g2d, renderer);
-        }
-
-        @Override
-        public void update() {
-            balls.update();
-        }
-
-        public ParticleRenderable configure(Configurable configure) {
-            this.configure = configure;
-            return this;
-        }
-    }
-
-    interface ParticleRenderer {
-        void render(Graphics2D g2d, int id, float[] x, float[] y, float[] vx, float[] vy);
-
-    }
-
-    static class WhiteTextParticleRenderer implements ParticleRenderer {
-        float r;
-
-        WhiteTextParticleRenderer(float r) {
-            this.r = r;
-        }
-
-        void setPaint(Graphics2D g2d, int id) {
-            g2d.setColor(Color.WHITE);
-        }
-
-        @Override
-        public void render(Graphics2D g2d, int id, float[] x, float[] y, float[] vx, float[] vy) {
-            setPaint(g2d, id);
-            g2d.drawString("The quick brown fox jumps over the lazy dog",
-                    (int)(x[id] - r), (int)(y[id] - r));
-            g2d.drawString("The quick brown fox jumps over the lazy dog",
-                    (int)(x[id] - r), (int)y[id]);
-            g2d.drawString("The quick brown fox jumps over the lazy dog",
-                    (int)(x[id] - r), (int)(y[id] + r));
-        }
-    }
-
-    static class TextParticleRenderer extends WhiteTextParticleRenderer {
-        Color[] colors;
-
-        float r;
-
-        TextParticleRenderer(int n, float r) {
-            super(r);
-            colors = new Color[n];
-            this.r = r;
-            for (int i = 0; i < n; i++) {
-                colors[i] = new Color((float) Math.random(),
-                        (float) Math.random(), (float) Math.random());
-            }
-        }
-
-        void setPaint(Graphics2D g2d, int id) {
-            g2d.setColor(colors[id % colors.length]);
-        }
-    }
-
-    static class PerfMeter {
-        private String name;
-        private int frame = 0;
-
-        private JPanel panel;
-
-        private long time;
-        private double execTime = 0;
-        private Color expColor = Color.RED;
-        AtomicBoolean waiting = new AtomicBoolean(false);
-        private double fps;
-
-        PerfMeter(String name) {
-            this.name = name;
-        }
-
-        PerfMeter exec(final Renderable renderable) throws Exception {
-            final CountDownLatch latch = new CountDownLatch(COUNT);
-            final CountDownLatch latchFrame = new CountDownLatch(1);
-            final long endTime = System.currentTimeMillis() + MAX_MEASURE_TIME;
-
-            final Frame f = new Frame();
-            f.addWindowListener(new WindowAdapter() {
-                @Override
-                public void windowClosed(WindowEvent e) {
-                    latchFrame.countDown();
-                }
-            });
-
-            SwingUtilities.invokeAndWait(new Runnable() {
-                @Override
-                public void run() {
-
-                    panel = new JPanel()
-                    {
-                        @Override
-                        protected void paintComponent(Graphics g) {
-
-                            super.paintComponent(g);
-                            time = System.nanoTime();
-                            Graphics2D g2d = (Graphics2D) g.create();
-                            renderable.setup(g2d);
-                            renderable.render(g2d);
-                            g2d.setColor(expColor);
-                            g.fillRect(0, 0, BW, BH);
-                        }
-                    };
-
-                    panel.setPreferredSize(new Dimension((int)(WIDTH + BW), (int)(HEIGHT + BH)));
-                    panel.setBackground(Color.BLACK);
-                    f.add(panel);
-                    //f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
-                    f.pack();
-                    f.setVisible(true);
-                }
-            });
-            Robot robot = new Robot();
-
-            Timer timer = new Timer(DELAY, e -> {
-
-                if (waiting.compareAndSet(false, true)) {
-                    Color c = robot.getPixelColor(
-                            panel.getTopLevelAncestor().getX() + panel.getTopLevelAncestor().getInsets().left + BW / 2,
-                            panel.getTopLevelAncestor().getY() + panel.getTopLevelAncestor().getInsets().top + BW / 2);
-                    if (isAlmostEqual(c, Color.BLUE)) {
-                        expColor = Color.RED;
-                    } else {
-                        expColor = Color.BLUE;
-                    }
-                    renderable.update();
-                    panel.getParent().repaint();
-
-                } else {
-                    while (!isAlmostEqual(
-                            robot.getPixelColor(
-                                    panel.getTopLevelAncestor().getX() + panel.getTopLevelAncestor().getInsets().left + BW/2,
-                                    panel.getTopLevelAncestor().getY() + panel.getTopLevelAncestor().getInsets().top + BH/2),
-                            expColor))
-                    {
-                        try {
-                            Thread.sleep(RESOLUTION);
-                        } catch (InterruptedException ex) {
-                            ex.printStackTrace();
-                        }
-                    }
-                    time = System.nanoTime() - time;
-                    execTime += time;
-                    frame++;
-                    waiting.set(false);
-                }
-
-                if (System.currentTimeMillis() < endTime) {
-                    latch.countDown();
-                } else {
-                    while(latch.getCount() > 0) latch.countDown();
-                }
-            });
-            timer.start();
-            latch.await();
-            SwingUtilities.invokeAndWait(() -> {
-                timer.stop();
-                f.setVisible(false);
-                f.dispose();
-            });
-
-            latchFrame.await();
-            if (execTime != 0 && frame != 0) {
-                fps = 1e9 / (execTime / frame);
-            } else {
-                fps = 0;
-            }
-
-            return this;
-        }
-
-        private void report() {
-            System.err.println(name + " : " + String.format("%.2f FPS", fps));
-        }
-
-        private boolean isAlmostEqual(Color c1, Color c2) {
-            return Math.abs(c1.getRed() - c2.getRed()) < COLOR_TOLERANCE ||
-                    Math.abs(c1.getGreen() - c2.getGreen()) < COLOR_TOLERANCE ||
-                    Math.abs(c1.getBlue() - c2.getBlue()) < COLOR_TOLERANCE;
-
-        }
-    }
-
-    private static final Particles balls = new Particles(N, R, BW, BH, WIDTH, HEIGHT);
-    private static final ParticleRenderer textRenderer = new TextParticleRenderer(N, R);
-
-    private static final Configurable TextLCD = (Graphics2D g2d) ->
-        g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
-                RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);
-
-    public void testTextBubblesLCD() throws Exception {
-        (new PerfMeter("TextLCD")).exec(createPR(textRenderer).configure(TextLCD)).report();
-    }
-
-    public static void main(String[] args)
-            throws InvocationTargetException, IllegalAccessException, NoSuchMethodException
-    {
-        RenderPerfLCDTest test = new RenderPerfLCDTest();
-
-        if (args.length > 0) {
-            for (String testCase : args) {
-                Method m = RenderPerfLCDTest.class.getDeclaredMethod(testCase);
-                m.invoke(test);
-            }
-        } else {
-            Method[] methods = RenderPerfLCDTest.class.getDeclaredMethods();
-            for (Method m : methods) {
-                if (m.getName().startsWith("test") && !ignoredTests.contains(m.getName())) {
-                    m.invoke(test);
-                }
-            }
-        }
-    }
-}
diff --git a/test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfTest.java b/test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfTest.java
index 3805c8d591479..51beaba5172e1 100644
--- a/test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfTest.java
+++ b/test/jdk/performance/client/RenderPerfTest/src/renderperf/RenderPerfTest.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, JetBrains s.r.o.. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -54,20 +55,21 @@
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.atomic.AtomicBoolean;
 
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
 import javax.imageio.ImageIO;
 import javax.swing.JFrame;
 import javax.swing.JPanel;
 import javax.swing.SwingUtilities;
-import javax.swing.Timer;
 import javax.swing.WindowConstants;
 
 public class RenderPerfTest {
     private static HashSet<String> ignoredTests = new HashSet<>();
 
     static {
-        ignoredTests.add("testWiredBoxAA");
+       // add ignored tests here
+       // ignoredTests.add("testMyIgnoredTest");
     }
 
     private final static int N = 1000;
@@ -76,12 +78,14 @@ public class RenderPerfTest {
     private final static float R = 25;
     private final static int BW = 50;
     private final static int BH = 50;
-    private final static int COUNT = 300;
-    private final static int DELAY = 10;
-    private final static int RESOLUTION = 5;
+    private final static int COUNT = 600;
+    private final static int CYCLE_DELAY = 3;
+    private final static int MAX_FRAME_CYCLES = 3000/CYCLE_DELAY;
+
     private final static int COLOR_TOLERANCE = 10;
-    private final static int MAX_MEASURE_TIME = 5000;
+    private final static int MAX_MEASURE_CYCLES = 6000/CYCLE_DELAY;
 
+    private final static Color[] marker = {Color.RED, Color.BLUE, Color.GREEN, Color.YELLOW, Color.ORANGE, Color.MAGENTA};
 
     interface Configurable {
         void configure(Graphics2D g2d);
@@ -276,6 +280,7 @@ static class LargeTextParticleRenderer extends TextParticleRenderer {
         @Override
         public void render(Graphics2D g2d, int id, float[] x, float[] y, float[] vx, float[] vy) {
             setPaint(g2d, id);
+            if (id % 100 != 0) return;
             Font font = new Font("LucidaGrande", Font.PLAIN, 32);
             g2d.setFont(font);
             g2d.drawString("The quick brown fox jumps over the lazy dog",
@@ -599,24 +604,24 @@ private static BufferedImage makeManagedBI(final int type) {
 
     static class PerfMeter {
         private String name;
-        private int frame = 0;
+
 
         private JPanel panel;
 
-        private long time;
         private double execTime = 0;
-        private Color expColor = Color.RED;
-        AtomicBoolean waiting = new AtomicBoolean(false);
+        private AtomicInteger markerIdx = new AtomicInteger(0);
+        private int renderedMarkerIdx = -1;
+        private AtomicLong markerPaintTime = new AtomicLong(0);
+
         private double fps;
+        private int skippedFrame = 0;
 
         PerfMeter(String name) {
             this.name = name;
         }
 
         PerfMeter exec(final Renderable renderable) throws Exception {
-            final CountDownLatch latch = new CountDownLatch(COUNT);
             final CountDownLatch latchFrame = new CountDownLatch(1);
-            final long endTime = System.currentTimeMillis() + MAX_MEASURE_TIME;
 
             final JFrame f = new JFrame();
             f.addWindowListener(new WindowAdapter() {
@@ -630,22 +635,27 @@ public void windowClosed(WindowEvent e) {
                 @Override
                 public void run() {
 
-                    panel = new JPanel()
-                    {
+                    panel = new JPanel() {
                         @Override
                         protected void paintComponent(Graphics g) {
-
                             super.paintComponent(g);
-                            time = System.nanoTime();
+                            int idx = markerIdx.get();
+                            if (idx != renderedMarkerIdx) {
+                                markerPaintTime.set(System.nanoTime());
+                            }
+
                             Graphics2D g2d = (Graphics2D) g.create();
                             renderable.setup(g2d);
                             renderable.render(g2d);
-                            g2d.setColor(expColor);
-                            g.fillRect(0, 0, BW, BH);
+                            g2d.setClip(null);
+                            g2d.setPaintMode();
+                            g2d.setColor(marker[idx]);
+                            g2d.fillRect(0, 0, BW, BH);
+                            renderedMarkerIdx = idx;
                         }
                     };
 
-                    panel.setPreferredSize(new Dimension((int)(WIDTH + BW), (int)(HEIGHT + BH)));
+                    panel.setPreferredSize(new Dimension((int) (WIDTH + BW), (int) (HEIGHT + BH)));
                     panel.setBackground(Color.BLACK);
                     f.add(panel);
                     f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
@@ -653,51 +663,51 @@ protected void paintComponent(Graphics g) {
                     f.setVisible(true);
                 }
             });
-            Robot robot = new Robot();
 
-            Timer timer = new Timer(DELAY, e -> {
+            Robot robot = new Robot();
+            int cycle = 0;
+            int frame = 0;
+            long paintTime = 0;
+            int maxFrameCycle = -1;
+            while (frame < COUNT) {
+                long t;
+                if ((t = markerPaintTime.getAndSet(0)) > 0) {
+                    paintTime = t;
+                    maxFrameCycle = cycle + MAX_FRAME_CYCLES;
+                }
 
-                if (waiting.compareAndSet(false, true)) {
+                if (paintTime > 0) {
                     Color c = robot.getPixelColor(
                             panel.getTopLevelAncestor().getX() + panel.getTopLevelAncestor().getInsets().left + BW / 2,
                             panel.getTopLevelAncestor().getY() + panel.getTopLevelAncestor().getInsets().top + BW / 2);
-                    if (isAlmostEqual(c, Color.BLUE)) {
-                        expColor = Color.RED;
-                    } else {
-                        expColor = Color.BLUE;
-                    }
-                    renderable.update();
-                    panel.getParent().repaint();
-
-                } else {
-                    while (!isAlmostEqual(
-                            robot.getPixelColor(
-                                    panel.getTopLevelAncestor().getX() + panel.getTopLevelAncestor().getInsets().left + BW/2,
-                                    panel.getTopLevelAncestor().getY() + panel.getTopLevelAncestor().getInsets().top + BH/2),
-                            expColor))
-                    {
-                        try {
-                            Thread.sleep(RESOLUTION);
-                        } catch (InterruptedException ex) {
-                            ex.printStackTrace();
-                        }
+
+                    if (isAlmostEqual(c, marker[markerIdx.get()])) {
+                        execTime += System.nanoTime() - paintTime;
+                        frame++;
+                        paintTime = 0;
+                        maxFrameCycle = -1;
+                        markerIdx.accumulateAndGet(marker.length, (x, y) -> (x + 1) % y);
+                        renderable.update();
+                        panel.getParent().repaint();
+                    } else if (cycle >= maxFrameCycle) {
+                        skippedFrame++;
+                        paintTime = 0;
+                        maxFrameCycle = -1;
+                        markerIdx.accumulateAndGet(marker.length, (x, y) -> (x + 1) % y);
+                        panel.getParent().repaint();
                     }
-                    time = System.nanoTime() - time;
-                    execTime += time;
-                    frame++;
-                    waiting.set(false);
                 }
-
-                if (System.currentTimeMillis() < endTime) {
-                    latch.countDown();
-                } else {
-                    while(latch.getCount() > 0) latch.countDown();
+                try {
+                    Thread.sleep(CYCLE_DELAY);
+                } catch (InterruptedException ex) {
+                    ex.printStackTrace();
                 }
-            });
-            timer.start();
-            latch.await();
+                if (cycle >= MAX_MEASURE_CYCLES) {
+                    break;
+                }
+                cycle++;
+            }
             SwingUtilities.invokeAndWait(() -> {
-                timer.stop();
                 f.setVisible(false);
                 f.dispose();
             });
@@ -713,12 +723,15 @@ protected void paintComponent(Graphics g) {
         }
 
         private void report() {
+            if (skippedFrame > 0) {
+                System.err.println(skippedFrame + " frame(s) skipped");
+            }
             System.err.println(name + " : " + String.format("%.2f FPS", fps));
         }
 
         private boolean isAlmostEqual(Color c1, Color c2) {
-            return Math.abs(c1.getRed() - c2.getRed()) < COLOR_TOLERANCE ||
-                    Math.abs(c1.getGreen() - c2.getGreen()) < COLOR_TOLERANCE ||
+            return Math.abs(c1.getRed() - c2.getRed()) < COLOR_TOLERANCE &&
+                    Math.abs(c1.getGreen() - c2.getGreen()) < COLOR_TOLERANCE &&
                     Math.abs(c1.getBlue() - c2.getBlue()) < COLOR_TOLERANCE;
 
         }