diff --git a/src/clpp11.hpp b/src/clpp11.hpp index 8d6a1127..8ac0523f 100644 --- a/src/clpp11.hpp +++ b/src/clpp11.hpp @@ -44,6 +44,7 @@ #include // std::accumulate #include // std::strlen #include // fprintf, stderr +#include // OpenCL #define CL_USE_DEPRECATED_OPENCL_1_1_APIS // to disable deprecation warnings @@ -355,6 +356,12 @@ class Device { std::string{"."} + std::to_string(GetInfo(CL_DEVICE_COMPUTE_CAPABILITY_MINOR_NV)); } + // Returns if the Nvidia chip is a Volta or later archicture (sm_70 or higher) + bool IsPostNVIDIAVolta() const { + assert(HasExtension("cl_nv_device_attribute_query")); + return GetInfo(CL_DEVICE_COMPUTE_CAPABILITY_MAJOR_NV) >= 7; + } + // Retrieves the above extra information (if present) std::string GetExtraInfo() const { if (HasExtension("cl_amd_device_attribute_query")) { return AMDBoardName(); } diff --git a/src/cupp11.hpp b/src/cupp11.hpp index a1cb1614..ce765844 100644 --- a/src/cupp11.hpp +++ b/src/cupp11.hpp @@ -327,6 +327,11 @@ class Device { std::string AMDBoardName() const { return ""; } std::string NVIDIAComputeCapability() const { return Capabilities(); } + // Returns if the Nvidia chip is a Volta or later archicture (major version 7 or higher) + bool IsPostNVIDIAVolta() const { + return GetInfo(CU_DEVICE_ATTRIBUTE_COMPUTE_CAPABILITY_MAJOR) >= 7; + } + // Retrieves the above extra information std::string GetExtraInfo() const { return NVIDIAComputeCapability(); } diff --git a/src/kernels/level3/xgemm_part1.opencl b/src/kernels/level3/xgemm_part1.opencl index 99d64c91..3cfc5dfb 100644 --- a/src/kernels/level3/xgemm_part1.opencl +++ b/src/kernels/level3/xgemm_part1.opencl @@ -114,13 +114,29 @@ R"( #define GLOBAL_MEM_FENCE 0 // Global synchronisation barrier for potential better performance #endif -// Intel subgroups (https://www.khronos.org/registry/OpenCL/extensions/intel/cl_intel_subgroups.txt) +#ifndef SUBGROUP_SHUFFLING_NVIDIA_PRE_VOLTA + #define SUBGROUP_SHUFFLING_NVIDIA_PRE_VOLTA 0 +#endif +#ifndef SUBGROUP_SHUFFLING_NVIDIA_POST_VOLTA + #define SUBGROUP_SHUFFLING_NVIDIA_POST_VOLTA 0 +#endif +#ifndef SUBGROUP_SHUFFLING_INTEL + #define SUBGROUP_SHUFFLING_INTEL 0 +#endif #ifndef USE_SUBGROUP_SHUFFLING #define USE_SUBGROUP_SHUFFLING 0 // Optionally enables subgroup shuffling for Intel GPUs #endif -#if USE_SUBGROUP_SHUFFLING == 1 + +// Intel subgroups (https://www.khronos.org/registry/OpenCL/extensions/intel/cl_intel_subgroups.txt) +#if USE_SUBGROUP_SHUFFLING == 1 && SUBGROUP_SHUFFLING_INTEL #define SUBGROUP_SIZE 8 // Assumes subgroup size is always 8 on Intel GPUs #endif + +// NVIDIA warps as subgroups using inline PTX (https://docs.nvidia.com/cuda/inline-ptx-assembly/index.html) +#if USE_SUBGROUP_SHUFFLING == 1 && (SUBGROUP_SHUFFLING_NVIDIA_PRE_VOLTA || SUBGROUP_SHUFFLING_NVIDIA_POST_VOLTA) + #define SUBGROUP_SIZE 32 // Assumes subgroup size is always 32 on NVIDIA GPUs +#endif + #if NWI != SUBGROUP_SIZE || MDIMC < SUBGROUP_SIZE #undef USE_SUBGROUP_SHUFFLING #define USE_SUBGROUP_SHUFFLING 0 // Disables subgroups in case the assumptions don't hold diff --git a/src/kernels/level3/xgemm_part3.opencl b/src/kernels/level3/xgemm_part3.opencl index c3920cb5..35ec735c 100644 --- a/src/kernels/level3/xgemm_part3.opencl +++ b/src/kernels/level3/xgemm_part3.opencl @@ -17,6 +17,44 @@ R"( // ================================================================================================= +// A common interface for subgroup functions + +#if USE_SUBGROUP_SHUFFLING == 1 + +INLINE_FUNC int clblast_get_sub_group_local_id() { + + // Intel extension + #if SUBGROUP_SHUFFLING_INTEL == 1 + return get_sub_group_local_id(); + + // Nvidia inline PTX + #elif SUBGROUP_SHUFFLING_NVIDIA_PRE_VOLTA == 1 || SUBGROUP_SHUFFLING_NVIDIA_POST_VOLTA == 1 + int ret; + asm volatile("mov.u32 %0, %%laneid;" : "=r"(ret) ); + return ret; + #endif +} + +INLINE_FUNC realN clblast_sub_group_shuffle(realN reg, int src) { + + // Intel extension + #if SUBGROUP_SHUFFLING_INTEL == 1 + return intel_sub_group_shuffle(reg, src); + + // Nvidia inline PTX + // Volta and later requires .sync shuffle instructions with an extra mask arg + #elif SUBGROUP_SHUFFLING_NVIDIA_PRE_VOLTA == 1 || SUBGROUP_SHUFFLING_NVIDIA_POST_VOLTA == 1 + realN ret; + #if SUBGROUP_SHUFFLING_NVIDIA_POST_VOLTA == 1 + asm volatile("shfl.sync.idx.b32 %0, %1, %2, 0x1f, 0xffffffff;" : "=f"(ret): "f"(reg), "r"(src)); + #else + asm volatile("shfl.idx.b32 %0, %1, %2, 0x1f;" : "=f"(ret): "f"(reg), "r"(src)); + #endif + return ret; + #endif +} +#endif + // Main body of the matrix-multiplication algorithm. It calls various (inlined) functions. INLINE_FUNC void XgemmBody(const int kSizeM, const int kSizeN, const int kSizeK, const __global realM* restrict agm, const __global realN* restrict bgm, @@ -130,7 +168,7 @@ INLINE_FUNC void XgemmBody(const int kSizeM, const int kSizeN, const int kSizeK, #elif GEMMK == 1 // Loads data: 2D global --> 2D private (matrix A). Partly, shuffled later among subgroups #if USE_SUBGROUP_SHUFFLING == 1 - const int _ni = get_sub_group_local_id(); + const int _ni = clblast_get_sub_group_local_id(); #pragma unroll for (int _ki = 0; _ki < KREG/VWN; _ki += 1) { apm[_ki] = GlobalToPrivateA2D(a_ptr, tid_y, _ni, kSizeK, idk, _ki); @@ -202,7 +240,7 @@ INLINE_FUNC void XgemmBody(const int kSizeM, const int kSizeN, const int kSizeK, for (int _ki = 0; _ki < KREG/VWN; _ki += 1) { const int index = _ni * (MWI/VWM) + _mi; #if USE_SUBGROUP_SHUFFLING == 1 - const realN aval = intel_sub_group_shuffle(apm[_ki], _ni); + const realN aval = clblast_sub_group_shuffle(apm[_ki], _ni); #else const realN aval = apm[_ni * (KREG/VWN) + _ki]; #endif diff --git a/src/utilities/compile.cpp b/src/utilities/compile.cpp index 05c29944..835f54b4 100644 --- a/src/utilities/compile.cpp +++ b/src/utilities/compile.cpp @@ -61,8 +61,22 @@ std::shared_ptr CompileFromSource( // For Intel GPUs with subgroup support, use subgroup shuffling. if (device.IsGPU() && device.HasExtension(kKhronosIntelSubgroups)) { header_string += "#define USE_SUBGROUP_SHUFFLING 1\n"; + header_string += "#define SUBGROUP_SHUFFLING_INTEL 1\n"; } + // For NVIDIA GPUs, inline PTX can provide subgroup support + if (device.IsGPU() && device.IsNVIDIA() && precision == Precision::kSingle) { + header_string += "#define USE_SUBGROUP_SHUFFLING 1\n"; + + // Nvidia needs to check pre or post volta due to new shuffle commands + if (device.IsPostNVIDIAVolta()) { + header_string += "#define SUBGROUP_SHUFFLING_NVIDIA_POST_VOLTA 1\n"; + } + else { + header_string += "#define SUBGROUP_SHUFFLING_NVIDIA_PRE_VOLTA 1\n"; + } + } + // Optionally adds a translation header from OpenCL kernels to CUDA kernels #ifdef CUDA_API header_string +=