TheCherno · October 17, 2025 07:36 · Nov 20, 2019 · Nov 16, 2019
diff --git a/Instrumentor.h b/Instrumentor.h
@@ -3,12 +3,12 @@
 
 // Usage: include this header file somewhere in your code (eg. precompiled header), and then use like:
 //
-// Instrumentor::Get().BeginSession("Session Name");   // Begin session 
+// Instrumentor::Get().BeginSession("Session Name");        // Begin session 
 // {
-//     InstrumentationTimer timer("Profiled Scope Name");      // Place code like this in scopes you'd like to include in profiling
+//     InstrumentationTimer timer("Profiled Scope Name");   // Place code like this in scopes you'd like to include in profiling
 //     // Code
 // }
-// Instrumentor::Get().EndSession();                   // End Session
+// Instrumentor::Get().EndSession();                        // End Session
 //
 // You will probably want to macro-fy this, to switch on/off easily and use things like __FUNCSIG__ for the profile name.
 //
@@ -96,8 +96,8 @@ class Instrumentor
 
     static Instrumentor& Get()
     {
-        static Instrumentor* instance = new Instrumentor();
-        return *instance;
+        static Instrumentor instance;
+        return instance;
     }
 };
 
@@ -130,6 +130,6 @@ class InstrumentationTimer
     }
 private:
     const char* m_Name;
-    std::chrono::time_point<std::chrono::steady_clock> m_StartTimepoint;
+    std::chrono::time_point<std::chrono::high_resolution_clock> m_StartTimepoint;
     bool m_Stopped;
 };
diff --git a/Instrumentor.h b/Instrumentor.h
@@ -0,0 +1,135 @@
+//
+// Basic instrumentation profiler by Cherno
+
+// Usage: include this header file somewhere in your code (eg. precompiled header), and then use like:
+//
+// Instrumentor::Get().BeginSession("Session Name");   // Begin session 
+// {
+//     InstrumentationTimer timer("Profiled Scope Name");      // Place code like this in scopes you'd like to include in profiling
+//     // Code
+// }
+// Instrumentor::Get().EndSession();                   // End Session
+//
+// You will probably want to macro-fy this, to switch on/off easily and use things like __FUNCSIG__ for the profile name.
+//
+#pragma once
+
+#include <string>
+#include <chrono>
+#include <algorithm>
+#include <fstream>
+
+#include <thread>
+
+struct ProfileResult
+{
+    std::string Name;
+    long long Start, End;
+    uint32_t ThreadID;
+};
+
+struct InstrumentationSession
+{
+    std::string Name;
+};
+
+class Instrumentor
+{
+private:
+    InstrumentationSession* m_CurrentSession;
+    std::ofstream m_OutputStream;
+    int m_ProfileCount;
+public:
+    Instrumentor()
+        : m_CurrentSession(nullptr), m_ProfileCount(0)
+    {
+    }
+
+    void BeginSession(const std::string& name, const std::string& filepath = "results.json")
+    {
+        m_OutputStream.open(filepath);
+        WriteHeader();
+        m_CurrentSession = new InstrumentationSession{ name };
+    }
+
+    void EndSession()
+    {
+        WriteFooter();
+        m_OutputStream.close();
+        delete m_CurrentSession;
+        m_CurrentSession = nullptr;
+        m_ProfileCount = 0;
+    }
+
+    void WriteProfile(const ProfileResult& result)
+    {
+        if (m_ProfileCount++ > 0)
+            m_OutputStream << ",";
+
+        std::string name = result.Name;
+        std::replace(name.begin(), name.end(), '"', '\'');
+
+        m_OutputStream << "{";
+        m_OutputStream << "\"cat\":\"function\",";
+        m_OutputStream << "\"dur\":" << (result.End - result.Start) << ',';
+        m_OutputStream << "\"name\":\"" << name << "\",";
+        m_OutputStream << "\"ph\":\"X\",";
+        m_OutputStream << "\"pid\":0,";
+        m_OutputStream << "\"tid\":" << result.ThreadID << ",";
+        m_OutputStream << "\"ts\":" << result.Start;
+        m_OutputStream << "}";
+
+        m_OutputStream.flush();
+    }
+
+    void WriteHeader()
+    {
+        m_OutputStream << "{\"otherData\": {},\"traceEvents\":[";
+        m_OutputStream.flush();
+    }
+
+    void WriteFooter()
+    {
+        m_OutputStream << "]}";
+        m_OutputStream.flush();
+    }
+
+    static Instrumentor& Get()
+    {
+        static Instrumentor* instance = new Instrumentor();
+        return *instance;
+    }
+};
+
+class InstrumentationTimer
+{
+public:
+    InstrumentationTimer(const char* name)
+        : m_Name(name), m_Stopped(false)
+    {
+        m_StartTimepoint = std::chrono::high_resolution_clock::now();
+    }
+
+    ~InstrumentationTimer()
+    {
+        if (!m_Stopped)
+            Stop();
+    }
+
+    void Stop()
+    {
+        auto endTimepoint = std::chrono::high_resolution_clock::now();
+
+        long long start = std::chrono::time_point_cast<std::chrono::microseconds>(m_StartTimepoint).time_since_epoch().count();
+        long long end = std::chrono::time_point_cast<std::chrono::microseconds>(endTimepoint).time_since_epoch().count();
+
+        uint32_t threadID = std::hash<std::thread::id>{}(std::this_thread::get_id());
+        Instrumentor::Get().WriteProfile({ m_Name, start, end, threadID });
+
+        m_Stopped = true;
+    }
+private:
+    const char* m_Name;
+    std::chrono::time_point<std::chrono::steady_clock> m_StartTimepoint;
+    bool m_Stopped;
+};