Added getCPUTicks() and getCPUTicksPerSeconds() functions.

source/mijin/util/os.cpp

@@ -10,6 +10,7 @@
     #include <mutex>
     #include <dlfcn.h>
     #include <pthread.h>
+    #include <time.h>
 #elif MIJIN_TARGET_OS == MIJIN_OS_WINDOWS
     #include <array>
     #include <malloc.h>
@@ -42,7 +43,16 @@ namespace mijin
 namespace
 {
 std::mutex gDlErrorMutex; // dlerror may not be thread-safe
-}
+
+const std::uint64_t gCPUClockResolution = []()
+{
+    struct timespec time;
+    [[maybe_unused]] const int result = clock_getres(CLOCK_PROCESS_CPUTIME_ID, &time);
+    MIJIN_ASSERT(result == 0, "Error getting cputime resolution.");
+    MIJIN_ASSERT(time.tv_sec == 0, "What kind of cpu clock is this?");
+    return static_cast<std::uint64_t>(time.tv_nsec);
+}();
+};
 #endif // MIJIN_TARGET_OS == MIJIN_OS_LINUX
 
 //
@@ -178,4 +188,26 @@ void alignedFree(void* ptr)
 #endif
 }
 
+std::uint64_t getCPUTicks() MIJIN_NOEXCEPT
+{
+#if MIJIN_TARGET_OS == MIJIN_OS_LINUX
+    struct timespec time;
+    [[maybe_unused]] const int result = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time);
+    MIJIN_ASSERT(result == 0, "Error getting cpu time.");
+    return (static_cast<std::uint64_t>(time.tv_sec) * 1e9 + time.tv_nsec) / gCPUClockResolution;
+#else
+    MIJIN_ERROR("TODO");
+    return 0;
+#endif
+}
+
+std::uint64_t getCPUTicksPerSecond() MIJIN_NOEXCEPT
+{
+#if MIJIN_TARGET_OS == MIJIN_OS_LINUX
+    return 1e9 / gCPUClockResolution;
+#else
+    MIJIN_ERROR("TODO");
+    return 0;
+#endif
+}
 } // namespace mijin

source/mijin/util/os.hpp

@@ -5,6 +5,7 @@
 #define MIJIN_UTIL_OS_HPP_INCLUDED 1
 
 #include <csignal>
+#include <cstdint>
 #include <string>
 #include <string_view>
 #include <utility>
@@ -85,6 +86,9 @@ void setCurrentThreadName(const char* threadName) MIJIN_NOEXCEPT;
 [[nodiscard]] void* alignedRealloc(void* ptr, std::size_t alignment, std::size_t size) MIJIN_NOEXCEPT;
 void alignedFree(void* ptr);
 
+[[nodiscard]] std::uint64_t getCPUTicks() MIJIN_NOEXCEPT;
+[[nodiscard]] std::uint64_t getCPUTicksPerSecond() MIJIN_NOEXCEPT;
+
 SharedLibrary::~SharedLibrary() MIJIN_NOEXCEPT
 {
     close();