avoid repeated calls to 'cuDriverGetVersion' or 'cuDeviceGetCount' fu…

…nction
Learning-Ray-Tracing-From-Zero · Feb 27, 2025 · 28b7b28 · 28b7b28
1 parent c12fc6d
commit 28b7b28
Showing 1 changed file with 18 additions and 17 deletions.
diff --git a/src/backends/cuda/cuda_device.cpp b/src/backends/cuda/cuda_device.cpp
@@ -1029,14 +1029,18 @@ static constexpr auto required_cuda_version_major = 11;
 static constexpr auto required_cuda_version_minor = 7;
 static constexpr auto required_cuda_version = required_cuda_version_major * 1000 + required_cuda_version_minor * 10;
 
-static void initialize() {
+[[nodiscard]]
+static std::pair<int, int> initialize() {
     // global init
+    auto driver_version { 0 };
+    auto device_count { 0 };
+
     static std::once_flag flag;
-    std::call_once(flag, [] {
+    std::call_once(flag, [&] {
         // CUDA
         LUISA_CHECK_CUDA(cuInit(0));
+
         // check driver version
-        auto driver_version = 0;
         LUISA_CHECK_CUDA(cuDriverGetVersion(&driver_version));
         auto driver_version_major = driver_version / 1000;
         auto driver_version_minor = (driver_version % 1000) / 10;
@@ -1048,25 +1052,23 @@ static void initialize() {
         LUISA_VERBOSE("Successfully initialized CUDA "
                       "backend with driver version {}.{}.",
                       driver_version_major, driver_version_minor);
+
+        // check device count
+        LUISA_CHECK_CUDA(cuDeviceGetCount(&device_count));
+        if (device_count == 0) {
+            LUISA_ERROR_WITH_LOCATION("No available device found for CUDA backend.");
+        }
     });
+
+    return { driver_version, device_count };
 }
 
 }// namespace detail
 
 CUDADevice::Handle::Handle(size_t index) noexcept {
-
-    detail::initialize();
-
-    // cuda
-    auto driver_version = 0;
-    LUISA_CHECK_CUDA(cuDriverGetVersion(&driver_version));
+    auto [driver_version, device_count] = detail::initialize();
     _driver_version = driver_version;
 
-    auto device_count = 0;
-    LUISA_CHECK_CUDA(cuDeviceGetCount(&device_count));
-    if (device_count == 0) {
-        LUISA_ERROR_WITH_LOCATION("No available device found for CUDA backend.");
-    }
     if (index == std::numeric_limits<size_t>::max()) { index = 0; }
     if (index >= device_count) {
         LUISA_WARNING_WITH_LOCATION(
@@ -1225,9 +1227,8 @@ LUISA_EXPORT_API void destroy(luisa::compute::DeviceInterface *device) noexcept
 
 LUISA_EXPORT_API void backend_device_names(luisa::vector<luisa::string> &names) noexcept {
     names.clear();
-    auto device_count = 0;
-    luisa::compute::cuda::detail::initialize();
-    LUISA_CHECK_CUDA(cuDeviceGetCount(&device_count));
+    auto device_count { 0 };
+    std::tie(std::ignore, device_count) = luisa::compute::cuda::detail::initialize();
     if (device_count > 0) {
         names.reserve(device_count);
         for (auto i = 0; i < device_count; i++) {