diff --git a/libc/startup/gpu/amdgpu/start.cpp b/libc/startup/gpu/amdgpu/start.cpp --- a/libc/startup/gpu/amdgpu/start.cpp +++ b/libc/startup/gpu/amdgpu/start.cpp @@ -17,8 +17,6 @@ static cpp::Atomic lock = 0; -static cpp::Atomic count = 0; - extern "C" uintptr_t __init_array_start[]; extern "C" uintptr_t __init_array_end[]; extern "C" uintptr_t __fini_array_start[]; @@ -27,10 +25,6 @@ using InitCallback = void(int, char **, char **); using FiniCallback = void(void); -static uint64_t get_grid_size() { - return gpu::get_num_threads() * gpu::get_num_blocks(); -} - static void call_init_array_callbacks(int argc, char **argv, char **env) { size_t init_array_size = __init_array_end - __init_array_start; for (size_t i = 0; i < init_array_size; ++i) @@ -43,56 +37,34 @@ reinterpret_cast(__fini_array_start[i])(); } -void initialize(int argc, char **argv, char **env, void *in, void *out, - void *buffer) { - // We need a single GPU thread to perform the initialization of the global - // constructors and data. We simply mask off all but a single thread and - // execute. - count.fetch_add(1, cpp::MemoryOrder::RELAXED); - if (gpu::get_thread_id() == 0 && gpu::get_block_id() == 0) { - // We need to set up the RPC client first in case any of the constructors - // require it. - rpc::client.reset(gpu::get_lane_size(), &lock, in, out, buffer); - - // We want the fini array callbacks to be run after other atexit - // callbacks are run. So, we register them before running the init - // array callbacks as they can potentially register their own atexit - // callbacks. - atexit(&call_fini_array_callbacks); - call_init_array_callbacks(argc, argv, env); - } - - // We wait until every single thread launched on the GPU has seen the - // initialization code. This will get very, very slow for high thread counts, - // but for testing purposes it is unlikely to matter. - while (count.load(cpp::MemoryOrder::RELAXED) != get_grid_size()) - rpc::sleep_briefly(); - gpu::sync_threads(); -} - -void finalize(int retval) { - // We wait until every single thread launched on the GPU has finished - // executing and reached the finalize region. - count.fetch_sub(1, cpp::MemoryOrder::RELAXED); - while (count.load(cpp::MemoryOrder::RELAXED) != 0) - rpc::sleep_briefly(); - gpu::sync_threads(); - if (gpu::get_thread_id() == 0 && gpu::get_block_id() == 0) { - // Only a single thread should call `exit` here, the rest should gracefully - // return from the kernel. This is so only one thread calls the destructors - // registred with 'atexit' above. - __llvm_libc::exit(retval); - } -} - } // namespace __llvm_libc extern "C" [[gnu::visibility("protected"), clang::amdgpu_kernel]] void -_start(int argc, char **argv, char **envp, int *ret, void *in, void *out, - void *buffer) { - __llvm_libc::initialize(argc, argv, envp, in, out, buffer); +_begin(int argc, char **argv, char **env, void *in, void *out, void *buffer) { + // We need to set up the RPC client first in case any of the constructors + // require it. + __llvm_libc::rpc::client.reset(__llvm_libc::gpu::get_lane_size(), + &__llvm_libc::lock, in, out, buffer); + + // We want the fini array callbacks to be run after other atexit + // callbacks are run. So, we register them before running the init + // array callbacks as they can potentially register their own atexit + // callbacks. + __llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks); + __llvm_libc::call_init_array_callbacks(argc, argv, env); +} +extern "C" [[gnu::visibility("protected"), clang::amdgpu_kernel]] void +_start(int argc, char **argv, char **envp, int *ret) { + // Invoke the 'main' function with every active thread that the user launched + // the _start kernel with. __atomic_fetch_or(ret, main(argc, argv, envp), __ATOMIC_RELAXED); +} - __llvm_libc::finalize(*ret); +extern "C" [[gnu::visibility("protected"), clang::amdgpu_kernel]] void +_end(int retval) { + // Only a single thread should call `exit` here, the rest should gracefully + // return from the kernel. This is so only one thread calls the destructors + // registred with 'atexit' above. + __llvm_libc::exit(retval); } diff --git a/libc/startup/gpu/nvptx/start.cpp b/libc/startup/gpu/nvptx/start.cpp --- a/libc/startup/gpu/nvptx/start.cpp +++ b/libc/startup/gpu/nvptx/start.cpp @@ -17,8 +17,6 @@ static cpp::Atomic lock = 0; -static cpp::Atomic count = 0; - extern "C" { // Nvidia's 'nvlink' linker does not provide these sections. We instead need // to manually create them and update the globals in the loader implememtation. @@ -31,10 +29,6 @@ using InitCallback = void(int, char **, char **); using FiniCallback = void(void); -static uint64_t get_grid_size() { - return gpu::get_num_threads() * gpu::get_num_blocks(); -} - static void call_init_array_callbacks(int argc, char **argv, char **env) { size_t init_array_size = __init_array_end - __init_array_start; for (size_t i = 0; i < init_array_size; ++i) @@ -47,59 +41,33 @@ reinterpret_cast(__fini_array_start[i])(); } -// TODO: Put this in a separate kernel and call it with one thread. -void initialize(int argc, char **argv, char **env, void *in, void *out, - void *buffer) { - // We need a single GPU thread to perform the initialization of the global - // constructors and data. We simply mask off all but a single thread and - // execute. - count.fetch_add(1, cpp::MemoryOrder::RELAXED); - if (gpu::get_thread_id() == 0 && gpu::get_block_id() == 0) { - // We need to set up the RPC client first in case any of the constructors - // require it. - rpc::client.reset(gpu::get_lane_size(), &lock, in, out, buffer); - - // We want the fini array callbacks to be run after other atexit - // callbacks are run. So, we register them before running the init - // array callbacks as they can potentially register their own atexit - // callbacks. - // FIXME: The function pointer escaping this TU causes warnings. - __llvm_libc::atexit(&call_fini_array_callbacks); - call_init_array_callbacks(argc, argv, env); - } - - // We wait until every single thread launched on the GPU has seen the - // initialization code. This will get very, very slow for high thread counts, - // but for testing purposes it is unlikely to matter. - while (count.load(cpp::MemoryOrder::RELAXED) != get_grid_size()) - rpc::sleep_briefly(); - gpu::sync_threads(); -} - -// TODO: Put this in a separate kernel and call it with one thread. -void finalize(int retval) { - // We wait until every single thread launched on the GPU has finished - // executing and reached the finalize region. - count.fetch_sub(1, cpp::MemoryOrder::RELAXED); - while (count.load(cpp::MemoryOrder::RELAXED) != 0) - rpc::sleep_briefly(); - gpu::sync_threads(); - if (gpu::get_thread_id() == 0 && gpu::get_block_id() == 0) { - // Only a single thread should call `exit` here, the rest should gracefully - // return from the kernel. This is so only one thread calls the destructors - // registred with 'atexit' above. - __llvm_libc::exit(retval); - } -} - } // namespace __llvm_libc extern "C" [[gnu::visibility("protected"), clang::nvptx_kernel]] void -_start(int argc, char **argv, char **envp, int *ret, void *in, void *out, - void *buffer) { - __llvm_libc::initialize(argc, argv, envp, in, out, buffer); +_begin(int argc, char **argv, char **env, void *in, void *out, void *buffer) { + // We need to set up the RPC client first in case any of the constructors + // require it. + __llvm_libc::rpc::client.reset(__llvm_libc::gpu::get_lane_size(), + &__llvm_libc::lock, in, out, buffer); + + // We want the fini array callbacks to be run after other atexit + // callbacks are run. So, we register them before running the init + // array callbacks as they can potentially register their own atexit + // callbacks. + __llvm_libc::atexit(&__llvm_libc::call_fini_array_callbacks); + __llvm_libc::call_init_array_callbacks(argc, argv, env); +} +extern "C" [[gnu::visibility("protected"), clang::nvptx_kernel]] void +_start(int argc, char **argv, char **envp, int *ret) { + // Invoke the 'main' function with every active thread that the user launched + // the _start kernel with. __atomic_fetch_or(ret, main(argc, argv, envp), __ATOMIC_RELAXED); +} - __llvm_libc::finalize(*ret); +extern "C" [[gnu::visibility("protected"), clang::nvptx_kernel]] void +_end(int retval) { + // To finis the execution we invoke all the callbacks registered via 'atexit' + // and then exit with the appropriate return value. + __llvm_libc::exit(retval); } diff --git a/libc/utils/gpu/loader/amdgpu/Loader.cpp b/libc/utils/gpu/loader/amdgpu/Loader.cpp --- a/libc/utils/gpu/loader/amdgpu/Loader.cpp +++ b/libc/utils/gpu/loader/amdgpu/Loader.cpp @@ -24,25 +24,35 @@ #include #include -/// The name of the kernel we will launch. All AMDHSA kernels end with '.kd'. -constexpr const char *KERNEL_START = "_start.kd"; - -/// The arguments to the '_start' kernel. -struct kernel_args_t { +/// The arguments to the '_begin' kernel. +struct begin_args_t { int argc; void *argv; void *envp; - void *ret; void *inbox; void *outbox; void *buffer; }; +/// The arguments to the '_start' kernel. +struct start_args_t { + int argc; + void *argv; + void *envp; + void *ret; +}; + +/// The arguments to the '_end' kernel. +struct end_args_t { + int argc; +}; + /// Print the error code and exit if \p code indicates an error. static void handle_error(hsa_status_t code) { if (code == HSA_STATUS_SUCCESS || code == HSA_STATUS_INFO_BREAK) return; + fprintf(stderr, "HSA encountered an error while executing\n"); const char *desc; if (hsa_status_string(code, &desc) != HSA_STATUS_SUCCESS) desc = "Unknown error"; @@ -145,6 +155,103 @@ return iterate_agent_memory_pools(agent, cb); } +template +hsa_status_t launch_kernel(hsa_agent_t dev_agent, hsa_executable_t executable, + hsa_amd_memory_pool_t kernargs_pool, + hsa_queue_t *queue, const LaunchParameters ¶ms, + const char *kernel_name, args_t kernel_args) { + // Look up the '_start' kernel in the loaded executable. + hsa_executable_symbol_t symbol; + if (hsa_status_t err = hsa_executable_get_symbol_by_name( + executable, kernel_name, &dev_agent, &symbol)) + return err; + + // Retrieve different properties of the kernel symbol used for launch. + uint64_t kernel; + uint32_t args_size; + uint32_t group_size; + uint32_t private_size; + + std::pair symbol_infos[] = { + {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_OBJECT, &kernel}, + {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_KERNARG_SEGMENT_SIZE, &args_size}, + {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_GROUP_SEGMENT_SIZE, &group_size}, + {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_PRIVATE_SEGMENT_SIZE, &private_size}}; + + for (auto &[info, value] : symbol_infos) + if (hsa_status_t err = hsa_executable_symbol_get_info(symbol, info, value)) + return err; + + // Allocate space for the kernel arguments on the host and allow the GPU agent + // to access it. + void *args; + if (hsa_status_t err = hsa_amd_memory_pool_allocate(kernargs_pool, args_size, + /*flags=*/0, &args)) + handle_error(err); + hsa_amd_agents_allow_access(1, &dev_agent, nullptr, args); + + // Initialie all the arguments (explicit and implicit) to zero, then set the + // explicit arguments to the values created above. + std::memset(args, 0, args_size); + std::memcpy(args, &kernel_args, sizeof(args_t)); + + // Obtain a packet from the queue. + uint64_t packet_id = hsa_queue_add_write_index_relaxed(queue, 1); + while (packet_id - hsa_queue_load_read_index_scacquire(queue) >= queue->size) + ; + + const uint32_t mask = queue->size - 1; + hsa_kernel_dispatch_packet_t *packet = + static_cast(queue->base_address) + + (packet_id & mask); + + // Set up the packet for exeuction on the device. We currently only launch + // with one thread on the device, forcing the rest of the wavefront to be + // masked off. + std::memset(packet, 0, sizeof(hsa_kernel_dispatch_packet_t)); + packet->setup = (1) << HSA_KERNEL_DISPATCH_PACKET_SETUP_DIMENSIONS; + packet->workgroup_size_x = 1; + packet->workgroup_size_y = 1; + packet->workgroup_size_z = 1; + packet->grid_size_x = 1; + packet->grid_size_y = 1; + packet->grid_size_z = 1; + packet->private_segment_size = private_size; + packet->group_segment_size = group_size; + packet->kernel_object = kernel; + packet->kernarg_address = args; + + // Create a signal to indicate when this packet has been completed. + if (hsa_status_t err = + hsa_signal_create(1, 0, nullptr, &packet->completion_signal)) + handle_error(err); + + // Initialize the packet header and set the doorbell signal to begin execution + // by the HSA runtime. + uint16_t setup = packet->setup; + uint16_t header = + (HSA_PACKET_TYPE_KERNEL_DISPATCH << HSA_PACKET_HEADER_TYPE) | + (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_SCACQUIRE_FENCE_SCOPE) | + (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_SCRELEASE_FENCE_SCOPE); + __atomic_store_n(&packet->header, header | (setup << 16), __ATOMIC_RELEASE); + hsa_signal_store_relaxed(queue->doorbell_signal, packet_id); + + // Wait until the kernel has completed execution on the device. Periodically + // check the RPC client for work to be performed on the server. + while (hsa_signal_wait_scacquire( + packet->completion_signal, HSA_SIGNAL_CONDITION_EQ, 0, + /*timeout_hint=*/1024, HSA_WAIT_STATE_ACTIVE) != 0) + handle_server(); + + // Destroy the resources acquired to launch the kernel and return. + if (hsa_status_t err = hsa_amd_memory_pool_free(args)) + handle_error(err); + if (hsa_status_t err = hsa_signal_destroy(packet->completion_signal)) + handle_error(err); + + return HSA_STATUS_SUCCESS; +} + int load(int argc, char **argv, char **envp, void *image, size_t size, const LaunchParameters ¶ms) { // Initialize the HSA runtime used to communicate with the device. @@ -169,18 +276,6 @@ if (hsa_status_t err = get_agent(&host_agent)) handle_error(err); - // Obtain a queue with the minimum (power of two) size, used to send commands - // to the HSA runtime and launch execution on the device. - uint64_t queue_size; - if (hsa_status_t err = hsa_agent_get_info( - dev_agent, HSA_AGENT_INFO_QUEUE_MIN_SIZE, &queue_size)) - handle_error(err); - hsa_queue_t *queue = nullptr; - if (hsa_status_t err = - hsa_queue_create(dev_agent, queue_size, HSA_QUEUE_TYPE_SINGLE, - nullptr, nullptr, UINT32_MAX, UINT32_MAX, &queue)) - handle_error(err); - // Load the code object's ISA information and executable data segments. hsa_code_object_t object; if (hsa_status_t err = hsa_code_object_deserialize(image, size, "", &object)) @@ -228,36 +323,6 @@ dev_agent, &coarsegrained_pool)) handle_error(err); - // Look up the '_start' kernel in the loaded executable. - hsa_executable_symbol_t symbol; - if (hsa_status_t err = hsa_executable_get_symbol_by_name( - executable, KERNEL_START, &dev_agent, &symbol)) - handle_error(err); - - // Retrieve different properties of the kernel symbol used for launch. - uint64_t kernel; - uint32_t args_size; - uint32_t group_size; - uint32_t private_size; - - std::pair symbol_infos[] = { - {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_OBJECT, &kernel}, - {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_KERNARG_SEGMENT_SIZE, &args_size}, - {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_GROUP_SEGMENT_SIZE, &group_size}, - {HSA_EXECUTABLE_SYMBOL_INFO_KERNEL_PRIVATE_SEGMENT_SIZE, &private_size}}; - - for (auto &[info, value] : symbol_infos) - if (hsa_status_t err = hsa_executable_symbol_get_info(symbol, info, value)) - handle_error(err); - - // Allocate space for the kernel arguments on the host and allow the GPU agent - // to access it. - void *args; - if (hsa_status_t err = hsa_amd_memory_pool_allocate(kernargs_pool, args_size, - /*flags=*/0, &args)) - handle_error(err); - hsa_amd_agents_allow_access(1, &dev_agent, nullptr, args); - // Allocate fine-grained memory on the host to hold the pointer array for the // copied argv and allow the GPU agent to access it. auto allocator = [&](uint64_t size) -> void * { @@ -313,69 +378,33 @@ hsa_amd_agents_allow_access(1, &dev_agent, nullptr, server_outbox); hsa_amd_agents_allow_access(1, &dev_agent, nullptr, buffer); - // Initialie all the arguments (explicit and implicit) to zero, then set the - // explicit arguments to the values created above. - std::memset(args, 0, args_size); - kernel_args_t *kernel_args = reinterpret_cast(args); - kernel_args->argc = argc; - kernel_args->argv = dev_argv; - kernel_args->envp = dev_envp; - kernel_args->ret = dev_ret; - kernel_args->inbox = server_outbox; - kernel_args->outbox = server_inbox; - kernel_args->buffer = buffer; - - // Obtain a packet from the queue. - uint64_t packet_id = hsa_queue_add_write_index_relaxed(queue, 1); - while (packet_id - hsa_queue_load_read_index_scacquire(queue) >= queue_size) - ; - - const uint32_t mask = queue_size - 1; - hsa_kernel_dispatch_packet_t *packet = - (hsa_kernel_dispatch_packet_t *)queue->base_address + (packet_id & mask); - - // Set up the packet for exeuction on the device. We currently only launch - // with one thread on the device, forcing the rest of the wavefront to be - // masked off. - std::memset(packet, 0, sizeof(hsa_kernel_dispatch_packet_t)); - packet->setup = (1 + (params.num_blocks_y * params.num_threads_y != 1) + - (params.num_blocks_z * params.num_threads_z != 1)) - << HSA_KERNEL_DISPATCH_PACKET_SETUP_DIMENSIONS; - packet->workgroup_size_x = params.num_threads_x; - packet->workgroup_size_y = params.num_threads_y; - packet->workgroup_size_z = params.num_threads_z; - packet->grid_size_x = params.num_blocks_x * params.num_threads_x; - packet->grid_size_y = params.num_blocks_y * params.num_threads_y; - packet->grid_size_z = params.num_blocks_z * params.num_threads_z; - packet->private_segment_size = private_size; - packet->group_segment_size = group_size; - packet->kernel_object = kernel; - packet->kernarg_address = args; + // Initialize the RPC server's buffer for host-device communication. + server.reset(wavefront_size, &lock, server_inbox, server_outbox, buffer); - // Create a signal to indicate when this packet has been completed. + // Obtain a queue with the minimum (power of two) size, used to send commands + // to the HSA runtime and launch execution on the device. + uint64_t queue_size; + if (hsa_status_t err = hsa_agent_get_info( + dev_agent, HSA_AGENT_INFO_QUEUE_MIN_SIZE, &queue_size)) + handle_error(err); + hsa_queue_t *queue = nullptr; if (hsa_status_t err = - hsa_signal_create(1, 0, nullptr, &packet->completion_signal)) + hsa_queue_create(dev_agent, queue_size, HSA_QUEUE_TYPE_MULTI, nullptr, + nullptr, UINT32_MAX, UINT32_MAX, &queue)) handle_error(err); - // Initialize the RPC server's buffer for host-device communication. - server.reset(wavefront_size, &lock, server_inbox, server_outbox, buffer); - - // Initialize the packet header and set the doorbell signal to begin execution - // by the HSA runtime. - uint16_t header = - (HSA_PACKET_TYPE_KERNEL_DISPATCH << HSA_PACKET_HEADER_TYPE) | - (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_ACQUIRE_FENCE_SCOPE) | - (HSA_FENCE_SCOPE_SYSTEM << HSA_PACKET_HEADER_RELEASE_FENCE_SCOPE); - __atomic_store_n(&packet->header, header | (packet->setup << 16), - __ATOMIC_RELEASE); - hsa_signal_store_relaxed(queue->doorbell_signal, packet_id); + LaunchParameters single_threaded_params = {1, 1, 1, 1, 1, 1}; + begin_args_t init_args = {argc, dev_argv, dev_envp, + server_outbox, server_inbox, buffer}; + if (hsa_status_t err = + launch_kernel(dev_agent, executable, kernargs_pool, queue, + single_threaded_params, "_begin.kd", init_args)) + handle_error(err); - // Wait until the kernel has completed execution on the device. Periodically - // check the RPC client for work to be performed on the server. - while (hsa_signal_wait_scacquire( - packet->completion_signal, HSA_SIGNAL_CONDITION_EQ, 0, - /*timeout_hint=*/1024, HSA_WAIT_STATE_ACTIVE) != 0) - handle_server(); + start_args_t args = {argc, dev_argv, dev_envp, dev_ret}; + if (hsa_status_t err = launch_kernel(dev_agent, executable, kernargs_pool, + queue, params, "_start.kd", args)) + handle_error(err); // Create a memory signal and copy the return value back from the device into // a new buffer. @@ -402,9 +431,13 @@ // Save the return value and perform basic clean-up. int ret = *static_cast(host_ret); - // Free the memory allocated for the device. - if (hsa_status_t err = hsa_amd_memory_pool_free(args)) + end_args_t fini_args = {ret}; + if (hsa_status_t err = + launch_kernel(dev_agent, executable, kernargs_pool, queue, + single_threaded_params, "_end.kd", fini_args)) handle_error(err); + + // Free the memory allocated for the device. if (hsa_status_t err = hsa_amd_memory_pool_free(dev_argv)) handle_error(err); if (hsa_status_t err = hsa_amd_memory_pool_free(dev_ret)) @@ -420,10 +453,6 @@ if (hsa_status_t err = hsa_signal_destroy(memory_signal)) handle_error(err); - - if (hsa_status_t err = hsa_signal_destroy(packet->completion_signal)) - handle_error(err); - if (hsa_status_t err = hsa_queue_destroy(queue)) handle_error(err); diff --git a/libc/utils/gpu/loader/nvptx/Loader.cpp b/libc/utils/gpu/loader/nvptx/Loader.cpp --- a/libc/utils/gpu/loader/nvptx/Loader.cpp +++ b/libc/utils/gpu/loader/nvptx/Loader.cpp @@ -30,17 +30,29 @@ using namespace llvm; using namespace object; -/// The arguments to the '_start' kernel. -struct kernel_args_t { +/// The arguments to the '_begin' kernel. +struct begin_args_t { int argc; void *argv; void *envp; - void *ret; void *inbox; void *outbox; void *buffer; }; +/// The arguments to the '_start' kernel. +struct start_args_t { + int argc; + void *argv; + void *envp; + void *ret; +}; + +/// The arguments to the '_end' kernel. +struct end_args_t { + int argc; +}; + static void handle_error(CUresult err) { if (err == CUDA_SUCCESS) return; @@ -170,6 +182,36 @@ return dev_memory; } +template +CUresult launch_kernel(CUmodule binary, CUstream stream, + const LaunchParameters ¶ms, const char *kernel_name, + args_t kernel_args) { + // look up the '_start' kernel in the loaded module. + CUfunction function; + if (CUresult err = cuModuleGetFunction(&function, binary, kernel_name)) + handle_error(err); + + // Set up the arguments to the '_start' kernel on the GPU. + uint64_t args_size = sizeof(args_t); + void *args_config[] = {CU_LAUNCH_PARAM_BUFFER_POINTER, &kernel_args, + CU_LAUNCH_PARAM_BUFFER_SIZE, &args_size, + CU_LAUNCH_PARAM_END}; + + // Call the kernel with the given arguments. + if (CUresult err = cuLaunchKernel( + function, params.num_blocks_x, params.num_blocks_y, + params.num_blocks_z, params.num_threads_x, params.num_threads_y, + params.num_threads_z, 0, stream, nullptr, args_config)) + handle_error(err); + + // Wait until the kernel has completed execution on the device. Periodically + // check the RPC client for work to be performed on the server. + while (cuStreamQuery(stream) == CUDA_ERROR_NOT_READY) + handle_server(); + + return CUDA_SUCCESS; +} + int load(int argc, char **argv, char **envp, void *image, size_t size, const LaunchParameters ¶ms) { @@ -197,11 +239,6 @@ if (CUresult err = cuModuleLoadDataEx(&binary, image, 0, nullptr, nullptr)) handle_error(err); - // look up the '_start' kernel in the loaded module. - CUfunction function; - if (CUresult err = cuModuleGetFunction(&function, binary, "_start")) - handle_error(err); - // Allocate pinned memory on the host to hold the pointer array for the // copied argv and allow the GPU device to access it. auto allocator = [&](uint64_t size) -> void * { @@ -242,35 +279,21 @@ if (!server_inbox || !server_outbox || !buffer) handle_error("Failed to allocate memory the RPC client / server."); - // Set up the arguments to the '_start' kernel on the GPU. - uint64_t args_size = sizeof(kernel_args_t); - kernel_args_t args; - std::memset(&args, 0, args_size); - args.argc = argc; - args.argv = dev_argv; - args.envp = dev_envp; - args.ret = reinterpret_cast(dev_ret); - args.inbox = server_outbox; - args.outbox = server_inbox; - args.buffer = buffer; - void *args_config[] = {CU_LAUNCH_PARAM_BUFFER_POINTER, &args, - CU_LAUNCH_PARAM_BUFFER_SIZE, &args_size, - CU_LAUNCH_PARAM_END}; - // Initialize the RPC server's buffer for host-device communication. server.reset(warp_size, &lock, server_inbox, server_outbox, buffer); - // Call the kernel with the given arguments. - if (CUresult err = cuLaunchKernel( - function, params.num_blocks_x, params.num_blocks_y, - params.num_blocks_z, params.num_threads_x, params.num_threads_y, - params.num_threads_z, 0, stream, nullptr, args_config)) + LaunchParameters single_threaded_params = {1, 1, 1, 1, 1, 1}; + // Call the kernel to + begin_args_t init_args = {argc, dev_argv, dev_envp, + server_outbox, server_inbox, buffer}; + if (CUresult err = launch_kernel(binary, stream, single_threaded_params, + "_begin", init_args)) handle_error(err); - // Wait until the kernel has completed execution on the device. Periodically - // check the RPC client for work to be performed on the server. - while (cuStreamQuery(stream) == CUDA_ERROR_NOT_READY) - handle_server(); + start_args_t args = {argc, dev_argv, dev_envp, + reinterpret_cast(dev_ret)}; + if (CUresult err = launch_kernel(binary, stream, params, "_start", args)) + handle_error(err); // Copy the return value back from the kernel and wait. int host_ret = 0; @@ -280,6 +303,11 @@ if (CUresult err = cuStreamSynchronize(stream)) handle_error(err); + end_args_t fini_args = {host_ret}; + if (CUresult err = launch_kernel(binary, stream, single_threaded_params, + "_end", fini_args)) + handle_error(err); + // Free the memory allocated for the device. if (CUresult err = cuMemFreeHost(*memory_or_err)) handle_error(err);