gpu_fdinfo: add power usage for intel gpu via hwmon

Author: 17314642

src/gpu.h

@@ -38,10 +38,10 @@ class GPU {
                 // For now we're only accepting one of these modules at once
                 // Might be possible that multiple can exist on a system in the future?
                 if (vendor_id == 0x8086)
-                    fdinfo = std::make_unique<GPU_fdinfo>("i915");
+                    fdinfo = std::make_unique<GPU_fdinfo>("i915", pci_dev);
 
                 if (vendor_id == 0x5143)
-                    fdinfo = std::make_unique<GPU_fdinfo>("msm");
+                    fdinfo = std::make_unique<GPU_fdinfo>("msm", pci_dev);
         }
 
         gpu_metrics get_metrics() {

src/gpu_fdinfo.cpp

@@ -108,30 +108,71 @@ float GPU_fdinfo::get_vram_usage() {
     return (float)total_val / 1024 / 1024;
 }
 
+void GPU_fdinfo::find_intel_hwmon() {
+    std::string device = "/sys/bus/pci/devices/";
+    device += pci_dev;
+    device += "/hwmon";
+
+    auto dir_iterator = fs::directory_iterator(device);
+    auto hwmon = dir_iterator->path().string();
+
+    if (hwmon.empty()) {
+        SPDLOG_DEBUG("Intel hwmon directory is empty.");
+        return;
+    }
+
+    hwmon += "/energy1_input";
+
+    SPDLOG_DEBUG("Intel hwmon found: hwmon = {}", hwmon);
+    energy_stream.open(hwmon);
+
+    if (!energy_stream.good())
+        SPDLOG_DEBUG("Intel hwmon: failed to open {}", hwmon);
+}
+
+float GPU_fdinfo::get_power_usage() {
+    if (!energy_stream.is_open())
+        return 0.f;
+
+    std::string energy_input_str;
+    uint64_t energy_input;
+
+    energy_stream.seekg(0);
+    std::getline(energy_stream, energy_input_str);
+    energy_input = std::stoull(energy_input_str);
+
+    return energy_input / 1'000'000;
+}
+
 void GPU_fdinfo::get_load() {
     while (!stop_thread) {
         std::unique_lock<std::mutex> lock(metrics_mutex);
         cond_var.wait(lock, [this]() { return !paused || stop_thread; });
 
         static uint64_t previous_gpu_time, previous_time, now, gpu_time_now;
+        static float power_usage_now, previous_power_usage;
 
         gpu_time_now = get_gpu_time();
+        power_usage_now = get_power_usage();
         now = os_time_get_nano();
 
         if (gpu_time_now > previous_gpu_time &&
             now - previous_time > METRICS_UPDATE_PERIOD_MS * 1'000'000) {
             float time_since_last = now - previous_time;
             float gpu_since_last = gpu_time_now - previous_gpu_time;
+            float power_usage_since_last = power_usage_now - previous_power_usage;
 
             auto result = int((gpu_since_last / time_since_last) * 100);
             if (result > 100)
                 result = 100;
 
             metrics.load = result;
             metrics.memoryUsed = get_vram_usage();
+            metrics.powerUsage = power_usage_since_last;
 
             previous_gpu_time = gpu_time_now;
             previous_time = now;
+            previous_power_usage = power_usage_now;
         }
     }
 }

src/gpu_fdinfo.h

@@ -18,7 +18,10 @@ class GPU_fdinfo {
         struct gpu_metrics metrics;
         std::vector<FILE*> fdinfo;
         const char* module;
+        const char* pci_dev;
         void find_fd();
+        void find_intel_hwmon();
+        std::ifstream energy_stream;
         std::thread thread;
         std::condition_variable cond_var;
         std::atomic<bool> stop_thread{false};
@@ -30,10 +33,15 @@ class GPU_fdinfo {
         std::string get_drm_engine_type();
         std::string get_drm_memory_type();
         float get_vram_usage();
+        float get_power_usage();
 
     public:
-        GPU_fdinfo(const char* module) : module(module) {
+        GPU_fdinfo(const char* module, const char* pci_dev) : module(module), pci_dev(pci_dev) {
             find_fd();
+
+            if (strstr(module, "i915"))
+                find_intel_hwmon();
+
             std::thread thread(&GPU_fdinfo::get_load, this);
             thread.detach();
         }