Patch including FPS computation logic on top of source code so far at https://vulkan-tutorial.com/Drawing_a_triangle/Drawing/Rendering_and_presentation (grab its source looking at the bottom of C++ link). Apply patch via `patch main.cpp < patch`

patch

--- main-ref.cpp	2020-04-06 15:22:30.210006554 +0700
+++ main2.cpp	2020-04-06 15:23:11.217588339 +0700
@@ -13,11 +13,13 @@
 #include <cstdint>
 #include <optional>
 #include <set>
+#include <iomanip>
 
 const int WIDTH = 800;
 const int HEIGHT = 600;
 
 const int MAX_FRAMES_IN_FLIGHT = 2;
+const float FPS_GRANULARITY_SEC = 1.0f; // how often to update FPS
 
 const std::vector<const char*> validationLayers = {
     "VK_LAYER_KHRONOS_validation"
@@ -106,6 +108,10 @@
     std::vector<VkFence> imagesInFlight;
     size_t currentFrame = 0;
 
+    uint32_t numRenderedFrames = 0;
+    float fps = 0.0f;
+    double prevTime = 0.0f;
+
     void initWindow() {
         glfwInit();
 
@@ -135,6 +141,16 @@
         while (!glfwWindowShouldClose(window)) {
             glfwPollEvents();
             drawFrame();
+
+	    ++numRenderedFrames;
+            const double currTime = glfwGetTime();
+            const double diffTime = currTime - prevTime;
+            if (diffTime >= FPS_GRANULARITY_SEC) {
+                prevTime = currTime;
+                fps = numRenderedFrames / diffTime;
+                std::cout << std::fixed << std::setprecision(2) << std::setfill('0') << fps << " FPS\n";
+                numRenderedFrames = 0;
+            }
         }
 
         vkDeviceWaitIdle(device);