SpeedBreaker v0.1.0

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

runtime/gpu/gpu_clock.cpp

@@ -0,0 +1,76 @@
+// SpeedBreaker runtime. GPL-3.0-or-later (see COPYING). See gpu_clock.h.
+#include <stdafx.h>
+#include "gpu_clock.h"
+
+namespace gpu::clock
+{
+    namespace
+    {
+        // trans_stat: a row per frequency, "[*] <Hz>: <transitions...> <ms at it>".
+        std::map<uint64_t, uint64_t> ReadTimes(const std::filesystem::path& file)
+        {
+            std::map<uint64_t, uint64_t> times;
+            FILE* f = fopen(file.c_str(), "r");
+            if (!f)
+                return times;
+            char line[1024];
+            while (fgets(line, sizeof(line), f))
+            {
+                const char* p = line;
+                while (*p == ' ' || *p == '*')
+                    p++;
+                char* end;
+                unsigned long long hz = strtoull(p, &end, 10);
+                if (end == p || *end != ':')
+                    continue;
+                unsigned long long last = 0;
+                for (p = end + 1;;)
+                {
+                    unsigned long long v = strtoull(p, &end, 10);
+                    if (end == p)
+                        break;
+                    last = v;
+                    p = end;
+                }
+                times[hz] = last;
+            }
+            fclose(f);
+            return times;
+        }
+
+        std::filesystem::path FindTransStat()
+        {
+#ifdef __linux__
+            std::error_code ec;
+            for (std::filesystem::directory_iterator it("/sys/class/devfreq", ec), end; !ec && it != end; it.increment(ec))
+            {
+                std::string name = it->path().filename().string();
+                if (name.find("gpu") != std::string::npos && std::filesystem::exists(it->path() / "trans_stat", ec))
+                    return it->path() / "trans_stat";
+            }
+#endif
+            return {};
+        }
+    }
+
+    double AverageMHzSinceLast()
+    {
+        static const std::filesystem::path file = FindTransStat();
+        static std::map<uint64_t, uint64_t> last;
+        if (file.empty())
+            return 0.0;
+        std::map<uint64_t, uint64_t> now = ReadTimes(file);
+        double weighted = 0.0, ms = 0.0;
+        for (const auto& [hz, t] : now)
+        {
+            auto it = last.find(hz);
+            if (it == last.end() || t < it->second)
+                continue;
+            weighted += double(hz) * double(t - it->second);
+            ms += double(t - it->second);
+        }
+        bool first = last.empty();
+        last = std::move(now);
+        return first || ms <= 0.0 ? 0.0 : weighted / ms / 1e6;
+    }
+}