better example

Author: danielsn

examples/cxx/profiling.cpp

@@ -22,44 +22,67 @@ int main() {
         auto profile = Profile::create({wall_time}, period);
         std::cout << "✅ Profile created" << std::endl;
 
-        // Add samples
+        // Add samples with realistic stack traces
         std::cout << "Adding samples..." << std::endl;
         for (int i = 0; i < 100; i++) {
-            // Create mapping
-            CxxMapping mapping{
-                0x10000000,              // memory_start
-                0x20000000,              // memory_limit
-                0,                       // file_offset
-                "/usr/lib/libexample.so", // filename
-                "abc123def456"           // build_id
-            };
+            // Keep dynamically generated strings alive for the duration of add_sample()
+            // The profile will intern them, so they can be freed after that call
+            std::vector<std::string> string_storage;
+            
+            CxxMapping mapping{0x10000000, 0x20000000, 0, "/usr/lib/libexample.so", "abc123"};
 
-            // Create function
-            auto func_name = "my_function_" + std::to_string(i % 10);
-            auto sys_name = "_Z11my_function" + std::to_string(i % 10) + "v";
-            CxxFunction function{func_name.c_str(), sys_name.c_str(), "/path/to/source.cpp"};
+            // Leaf frame - where the CPU was actually spending time
+            string_storage.push_back("hot_function_" + std::to_string(i % 3));
+            string_storage.push_back("_Z12hot_function" + std::to_string(i % 3) + "v");
+            CxxFunction leaf_func{string_storage[0].c_str(), string_storage[1].c_str(), "/src/hot_path.cpp"};
+            CxxLocation leaf_frame{
+                mapping, leaf_func,
+                static_cast<uint64_t>(0x10003000 + (i % 3) * 0x100),
+                100 + (i % 3) * 10
+            };
 
-            // Create location
-            CxxLocation location{
-                mapping,
-                function,
-                static_cast<uint64_t>(0x12345678 + i * 0x100), // address
-                42 + i                                           // line
+            // Middle frame - intermediate call
+            string_storage.push_back("process_request_" + std::to_string(i % 5));
+            string_storage.push_back("_Z15process_request" + std::to_string(i % 5) + "v");
+            CxxFunction mid_func{string_storage[2].c_str(), string_storage[3].c_str(), "/src/handler.cpp"};
+            CxxLocation mid_frame{
+                mapping, mid_func,
+                static_cast<uint64_t>(0x10002000 + (i % 5) * 0x80),
+                50 + (i % 5) * 5
             };
 
+            // Root frame - entry point
+            CxxFunction root_func{"main", "main", "/src/main.cpp"};
+            CxxLocation root_frame{mapping, root_func, 0x10001000, 42};
+            
             // Create labels
             CxxLabel thread_label{"thread_id", "", static_cast<int64_t>(i % 4), ""};
-            CxxLabel counter_label{"unique_counter", "", static_cast<int64_t>(i), ""};
+            CxxLabel counter_label{"sample_id", "", static_cast<int64_t>(i), ""};
 
-            // Create sample using initializer lists
-            int64_t wall_time_value = 1000000; // 1ms
-            CxxSample sample{
-                {location},                    // locations
-                {wall_time_value},             // values
-                {thread_label, counter_label}  // labels
-            };
+            // Create sample with stack trace (3-4 frames depending on sample)
+            int64_t wall_time_value = 1000000 + (i % 1000) * 1000; // 1-2ms
 
-            profile->add_sample(sample);
+            if (i % 7 == 0) {
+                // Deeper stack (4 frames)
+                CxxFunction worker_func{"worker_loop", "_Z11worker_loopv", "/src/worker.cpp"};
+                CxxLocation worker_frame{mapping, worker_func, 0x10000500, 25};
+                
+                CxxSample sample{
+                    {leaf_frame, mid_frame, root_frame, worker_frame},  // 4-frame stack
+                    {wall_time_value},
+                    {thread_label, counter_label}
+                };
+                profile->add_sample(sample);
+            } else {
+                // Normal stack (3 frames)
+                CxxSample sample{
+                    {leaf_frame, mid_frame, root_frame},  // 3-frame stack
+                    {wall_time_value},
+                    {thread_label, counter_label}
+                };
+                profile->add_sample(sample);
+            }
+            // string_storage vector destroyed here, but profile has already interned the strings
         }
 
         std::cout << "✅ Added 100 samples" << std::endl;