1122 lines
39 KiB
Plaintext
1122 lines
39 KiB
Plaintext
/*!
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* Copyright 2017-2020 XGBoost contributors
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*/
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#pragma once
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#include <thrust/device_ptr.h>
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#include <thrust/device_vector.h>
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#include <thrust/device_malloc_allocator.h>
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#include <thrust/iterator/discard_iterator.h>
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#include <thrust/iterator/transform_output_iterator.h>
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#include <thrust/system/cuda/error.h>
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#include <thrust/system_error.h>
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#include <thrust/execution_policy.h>
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#include <thrust/transform_scan.h>
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#include <thrust/logical.h>
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#include <thrust/gather.h>
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#include <thrust/unique.h>
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#include <thrust/binary_search.h>
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#include <rabit/rabit.h>
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#include <cub/cub.cuh>
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#include <cub/util_allocator.cuh>
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#include <algorithm>
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#include <chrono>
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#include <numeric>
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#include <sstream>
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#include <string>
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#include <vector>
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#include "xgboost/logging.h"
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#include "xgboost/host_device_vector.h"
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#include "xgboost/span.h"
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#include "common.h"
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#ifdef XGBOOST_USE_NCCL
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#include "nccl.h"
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#endif // XGBOOST_USE_NCCL
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#if defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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#include "rmm/mr/device/per_device_resource.hpp"
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#include "rmm/mr/device/thrust_allocator_adaptor.hpp"
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#endif // defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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#if !defined(__CUDA_ARCH__) || __CUDA_ARCH__ >= 600 || defined(__clang__)
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#else // In device code and CUDA < 600
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__device__ __forceinline__ double atomicAdd(double* address, double val) { // NOLINT
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unsigned long long int* address_as_ull =
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(unsigned long long int*)address; // NOLINT
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unsigned long long int old = *address_as_ull, assumed; // NOLINT
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do {
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assumed = old;
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old = atomicCAS(address_as_ull, assumed,
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__double_as_longlong(val + __longlong_as_double(assumed)));
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// Note: uses integer comparison to avoid hang in case of NaN (since NaN !=
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// NaN)
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} while (assumed != old);
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return __longlong_as_double(old);
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}
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#endif
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namespace dh {
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namespace detail {
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template <size_t size>
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struct AtomicDispatcher;
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template <>
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struct AtomicDispatcher<sizeof(uint32_t)> {
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using Type = unsigned int; // NOLINT
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static_assert(sizeof(Type) == sizeof(uint32_t), "Unsigned should be of size 32 bits.");
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};
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template <>
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struct AtomicDispatcher<sizeof(uint64_t)> {
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using Type = unsigned long long; // NOLINT
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static_assert(sizeof(Type) == sizeof(uint64_t), "Unsigned long long should be of size 64 bits.");
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};
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} // namespace detail
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} // namespace dh
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// atomicAdd is not defined for size_t.
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template <typename T = size_t,
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std::enable_if_t<std::is_same<size_t, T>::value &&
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!std::is_same<size_t, unsigned long long>::value> * = // NOLINT
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nullptr>
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T __device__ __forceinline__ atomicAdd(T *addr, T v) { // NOLINT
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using Type = typename dh::detail::AtomicDispatcher<sizeof(T)>::Type;
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Type ret = ::atomicAdd(reinterpret_cast<Type *>(addr), static_cast<Type>(v));
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return static_cast<T>(ret);
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}
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namespace dh {
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#ifdef XGBOOST_USE_NCCL
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#define safe_nccl(ans) ThrowOnNcclError((ans), __FILE__, __LINE__)
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inline ncclResult_t ThrowOnNcclError(ncclResult_t code, const char *file,
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int line) {
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if (code != ncclSuccess) {
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std::stringstream ss;
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ss << "NCCL failure :" << ncclGetErrorString(code) << " ";
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ss << file << "(" << line << ")";
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throw std::runtime_error(ss.str());
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}
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return code;
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}
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#endif
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inline int32_t CudaGetPointerDevice(void* ptr) {
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int32_t device = -1;
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cudaPointerAttributes attr;
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dh::safe_cuda(cudaPointerGetAttributes(&attr, ptr));
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device = attr.device;
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return device;
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}
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inline size_t AvailableMemory(int device_idx) {
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size_t device_free = 0;
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size_t device_total = 0;
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safe_cuda(cudaSetDevice(device_idx));
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dh::safe_cuda(cudaMemGetInfo(&device_free, &device_total));
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return device_free;
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}
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inline size_t TotalMemory(int device_idx) {
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size_t device_free = 0;
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size_t device_total = 0;
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safe_cuda(cudaSetDevice(device_idx));
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dh::safe_cuda(cudaMemGetInfo(&device_free, &device_total));
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return device_total;
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}
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/**
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* \fn inline int MaxSharedMemory(int device_idx)
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*
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* \brief Maximum shared memory per block on this device.
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*
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* \param device_idx Zero-based index of the device.
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*/
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inline size_t MaxSharedMemory(int device_idx) {
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int max_shared_memory = 0;
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dh::safe_cuda(cudaDeviceGetAttribute
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(&max_shared_memory, cudaDevAttrMaxSharedMemoryPerBlock,
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device_idx));
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return size_t(max_shared_memory);
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}
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/**
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* \fn inline int MaxSharedMemoryOptin(int device_idx)
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*
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* \brief Maximum dynamic shared memory per thread block on this device
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that can be opted into when using cudaFuncSetAttribute().
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*
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* \param device_idx Zero-based index of the device.
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*/
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inline size_t MaxSharedMemoryOptin(int device_idx) {
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int max_shared_memory = 0;
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dh::safe_cuda(cudaDeviceGetAttribute
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(&max_shared_memory, cudaDevAttrMaxSharedMemoryPerBlockOptin,
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device_idx));
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return size_t(max_shared_memory);
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}
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inline void CheckComputeCapability() {
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for (int d_idx = 0; d_idx < xgboost::common::AllVisibleGPUs(); ++d_idx) {
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cudaDeviceProp prop;
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safe_cuda(cudaGetDeviceProperties(&prop, d_idx));
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std::ostringstream oss;
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oss << "CUDA Capability Major/Minor version number: " << prop.major << "."
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<< prop.minor << " is insufficient. Need >=3.5";
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int failed = prop.major < 3 || (prop.major == 3 && prop.minor < 5);
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if (failed) LOG(WARNING) << oss.str() << " for device: " << d_idx;
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}
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}
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XGBOOST_DEV_INLINE void AtomicOrByte(unsigned int *__restrict__ buffer,
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size_t ibyte, unsigned char b) {
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atomicOr(&buffer[ibyte / sizeof(unsigned int)],
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static_cast<unsigned int>(b)
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<< (ibyte % (sizeof(unsigned int)) * 8));
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}
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template <typename T>
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__device__ xgboost::common::Range GridStrideRange(T begin, T end) {
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begin += blockDim.x * blockIdx.x + threadIdx.x;
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xgboost::common::Range r(begin, end);
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r.Step(gridDim.x * blockDim.x);
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return r;
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}
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template <typename T>
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__device__ xgboost::common::Range BlockStrideRange(T begin, T end) {
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begin += threadIdx.x;
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xgboost::common::Range r(begin, end);
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r.Step(blockDim.x);
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return r;
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}
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// Threadblock iterates over range, filling with value. Requires all threads in
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// block to be active.
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template <typename IterT, typename ValueT>
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__device__ void BlockFill(IterT begin, size_t n, ValueT value) {
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for (auto i : BlockStrideRange(static_cast<size_t>(0), n)) {
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begin[i] = value;
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}
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}
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/*
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* Kernel launcher
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*/
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template <typename L>
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__global__ void LaunchNKernel(size_t begin, size_t end, L lambda) {
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for (auto i : GridStrideRange(begin, end)) {
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lambda(i);
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}
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}
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template <typename L>
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__global__ void LaunchNKernel(int device_idx, size_t begin, size_t end,
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L lambda) {
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for (auto i : GridStrideRange(begin, end)) {
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lambda(i, device_idx);
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}
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}
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/* \brief A wrapper around kernel launching syntax, used to guard against empty input.
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*
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* - nvcc fails to deduce template argument when kernel is a template accepting __device__
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* function as argument. Hence functions like `LaunchN` cannot use this wrapper.
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*
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* - With c++ initialization list `{}` syntax, you are forced to comply with the CUDA type
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* spcification.
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*/
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class LaunchKernel {
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size_t shmem_size_;
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cudaStream_t stream_;
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dim3 grids_;
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dim3 blocks_;
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public:
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LaunchKernel(uint32_t _grids, uint32_t _blk, size_t _shmem=0, cudaStream_t _s=nullptr) :
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grids_{_grids, 1, 1}, blocks_{_blk, 1, 1}, shmem_size_{_shmem}, stream_{_s} {}
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LaunchKernel(dim3 _grids, dim3 _blk, size_t _shmem=0, cudaStream_t _s=nullptr) :
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grids_{_grids}, blocks_{_blk}, shmem_size_{_shmem}, stream_{_s} {}
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template <typename K, typename... Args>
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void operator()(K kernel, Args... args) {
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if (XGBOOST_EXPECT(grids_.x * grids_.y * grids_.z == 0, false)) {
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LOG(DEBUG) << "Skipping empty CUDA kernel.";
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return;
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}
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kernel<<<grids_, blocks_, shmem_size_, stream_>>>(args...); // NOLINT
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}
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};
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template <int ITEMS_PER_THREAD = 8, int BLOCK_THREADS = 256, typename L>
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inline void LaunchN(int device_idx, size_t n, cudaStream_t stream, L lambda) {
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if (n == 0) {
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return;
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}
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const int GRID_SIZE =
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static_cast<int>(xgboost::common::DivRoundUp(n, ITEMS_PER_THREAD * BLOCK_THREADS));
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LaunchNKernel<<<GRID_SIZE, BLOCK_THREADS, 0, stream>>>( // NOLINT
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static_cast<size_t>(0), n, lambda);
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}
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// Default stream version
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template <int ITEMS_PER_THREAD = 8, int BLOCK_THREADS = 256, typename L>
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inline void LaunchN(int device_idx, size_t n, L lambda) {
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LaunchN<ITEMS_PER_THREAD, BLOCK_THREADS>(device_idx, n, nullptr, lambda);
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}
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namespace detail {
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/** \brief Keeps track of global device memory allocations. Thread safe.*/
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class MemoryLogger {
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// Information for a single device
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struct DeviceStats {
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size_t currently_allocated_bytes{ 0 };
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size_t peak_allocated_bytes{ 0 };
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size_t num_allocations{ 0 };
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size_t num_deallocations{ 0 };
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std::map<void *, size_t> device_allocations;
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void RegisterAllocation(void *ptr, size_t n) {
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device_allocations[ptr] = n;
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currently_allocated_bytes += n;
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peak_allocated_bytes =
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std::max(peak_allocated_bytes, currently_allocated_bytes);
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num_allocations++;
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CHECK_GT(num_allocations, num_deallocations);
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}
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void RegisterDeallocation(void *ptr, size_t n, int current_device) {
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auto itr = device_allocations.find(ptr);
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if (itr == device_allocations.end()) {
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LOG(FATAL) << "Attempting to deallocate " << n << " bytes on device "
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<< current_device << " that was never allocated ";
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}
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num_deallocations++;
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CHECK_LE(num_deallocations, num_allocations);
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currently_allocated_bytes -= itr->second;
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device_allocations.erase(itr);
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}
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};
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DeviceStats stats_;
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std::mutex mutex_;
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public:
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void RegisterAllocation(void *ptr, size_t n) {
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if (!xgboost::ConsoleLogger::ShouldLog(xgboost::ConsoleLogger::LV::kDebug)) {
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return;
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}
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std::lock_guard<std::mutex> guard(mutex_);
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int current_device;
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safe_cuda(cudaGetDevice(¤t_device));
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stats_.RegisterAllocation(ptr, n);
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}
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void RegisterDeallocation(void *ptr, size_t n) {
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if (!xgboost::ConsoleLogger::ShouldLog(xgboost::ConsoleLogger::LV::kDebug)) {
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return;
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}
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std::lock_guard<std::mutex> guard(mutex_);
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int current_device;
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safe_cuda(cudaGetDevice(¤t_device));
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stats_.RegisterDeallocation(ptr, n, current_device);
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}
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size_t PeakMemory() const {
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return stats_.peak_allocated_bytes;
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}
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size_t CurrentlyAllocatedBytes() const {
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return stats_.currently_allocated_bytes;
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}
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void Clear()
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{
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stats_ = DeviceStats();
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}
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void Log() {
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if (!xgboost::ConsoleLogger::ShouldLog(xgboost::ConsoleLogger::LV::kDebug)) {
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return;
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}
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std::lock_guard<std::mutex> guard(mutex_);
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int current_device;
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safe_cuda(cudaGetDevice(¤t_device));
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LOG(CONSOLE) << "======== Device " << current_device << " Memory Allocations: "
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<< " ========";
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LOG(CONSOLE) << "Peak memory usage: "
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<< stats_.peak_allocated_bytes / 1048576 << "MiB";
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LOG(CONSOLE) << "Number of allocations: " << stats_.num_allocations;
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}
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};
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} // namespace detail
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inline detail::MemoryLogger &GlobalMemoryLogger() {
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static detail::MemoryLogger memory_logger;
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return memory_logger;
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}
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// dh::DebugSyncDevice(__FILE__, __LINE__);
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inline void DebugSyncDevice(std::string file="", int32_t line = -1) {
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if (file != "" && line != -1) {
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auto rank = rabit::GetRank();
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LOG(DEBUG) << "R:" << rank << ": " << file << ":" << line;
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}
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safe_cuda(cudaDeviceSynchronize());
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safe_cuda(cudaGetLastError());
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}
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namespace detail {
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#if defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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template <typename T>
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using XGBBaseDeviceAllocator = rmm::mr::thrust_allocator<T>;
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#else // defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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template <typename T>
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using XGBBaseDeviceAllocator = thrust::device_malloc_allocator<T>;
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#endif // defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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/**
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* \brief Default memory allocator, uses cudaMalloc/Free and logs allocations if verbose.
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*/
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template <class T>
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struct XGBDefaultDeviceAllocatorImpl : XGBBaseDeviceAllocator<T> {
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using SuperT = XGBBaseDeviceAllocator<T>;
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using pointer = thrust::device_ptr<T>; // NOLINT
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template<typename U>
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struct rebind // NOLINT
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{
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using other = XGBDefaultDeviceAllocatorImpl<U>; // NOLINT
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};
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pointer allocate(size_t n) { // NOLINT
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pointer ptr = SuperT::allocate(n);
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GlobalMemoryLogger().RegisterAllocation(ptr.get(), n * sizeof(T));
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return ptr;
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}
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void deallocate(pointer ptr, size_t n) { // NOLINT
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GlobalMemoryLogger().RegisterDeallocation(ptr.get(), n * sizeof(T));
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SuperT::deallocate(ptr, n);
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}
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#if defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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XGBDefaultDeviceAllocatorImpl()
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: SuperT(rmm::mr::get_current_device_resource(), cudaStream_t{nullptr}) {}
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#endif // defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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};
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/**
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* \brief Caching memory allocator, uses cub::CachingDeviceAllocator as a back-end, unless
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* RMM pool allocator is enabled. Does not initialise memory on construction.
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*/
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template <class T>
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struct XGBCachingDeviceAllocatorImpl : XGBBaseDeviceAllocator<T> {
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using SuperT = XGBBaseDeviceAllocator<T>;
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using pointer = thrust::device_ptr<T>; // NOLINT
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template<typename U>
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struct rebind // NOLINT
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{
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using other = XGBCachingDeviceAllocatorImpl<U>; // NOLINT
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};
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cub::CachingDeviceAllocator& GetGlobalCachingAllocator() {
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// Configure allocator with maximum cached bin size of ~1GB and no limit on
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// maximum cached bytes
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static cub::CachingDeviceAllocator *allocator = new cub::CachingDeviceAllocator(2, 9, 29);
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return *allocator;
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}
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pointer allocate(size_t n) { // NOLINT
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pointer ptr;
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if (use_cub_allocator_) {
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T* raw_ptr{nullptr};
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GetGlobalCachingAllocator().DeviceAllocate(reinterpret_cast<void**>(&raw_ptr), n * sizeof(T));
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ptr = pointer(raw_ptr);
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} else {
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ptr = SuperT::allocate(n);
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}
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GlobalMemoryLogger().RegisterAllocation(ptr.get(), n * sizeof(T));
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return ptr;
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}
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void deallocate(pointer ptr, size_t n) { // NOLINT
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GlobalMemoryLogger().RegisterDeallocation(ptr.get(), n * sizeof(T));
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if (use_cub_allocator_) {
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GetGlobalCachingAllocator().DeviceFree(ptr.get());
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} else {
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SuperT::deallocate(ptr, n);
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}
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}
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#if defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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XGBCachingDeviceAllocatorImpl()
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: SuperT(rmm::mr::get_current_device_resource(), cudaStream_t{nullptr}) {
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std::string symbol{typeid(*SuperT::resource()).name()};
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if (symbol.find("pool_memory_resource") != std::string::npos
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|| symbol.find("binning_memory_resource") != std::string::npos
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|| symbol.find("arena_memory_resource") != std::string::npos) {
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use_cub_allocator_ = false;
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}
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}
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#endif // defined(XGBOOST_USE_RMM) && XGBOOST_USE_RMM == 1
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private:
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bool use_cub_allocator_{true};
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};
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} // namespace detail
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// Declare xgboost allocators
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// Replacement of allocator with custom backend should occur here
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template <typename T>
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using XGBDeviceAllocator = detail::XGBDefaultDeviceAllocatorImpl<T>;
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/*! Be careful that the initialization constructor is a no-op, which means calling
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* `vec.resize(n)` won't initialize the memory region to 0. Instead use
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* `vec.resize(n, 0)`*/
|
|
template <typename T>
|
|
using XGBCachingDeviceAllocator = detail::XGBCachingDeviceAllocatorImpl<T>;
|
|
/** \brief Specialisation of thrust device vector using custom allocator. */
|
|
template <typename T>
|
|
using device_vector = thrust::device_vector<T, XGBDeviceAllocator<T>>; // NOLINT
|
|
template <typename T>
|
|
using caching_device_vector = thrust::device_vector<T, XGBCachingDeviceAllocator<T>>; // NOLINT
|
|
|
|
// Faster to instantiate than caching_device_vector and invokes no synchronisation
|
|
// Use this where vector functionality (e.g. resize) is not required
|
|
template <typename T>
|
|
class TemporaryArray {
|
|
public:
|
|
using AllocT = XGBCachingDeviceAllocator<T>;
|
|
using value_type = T; // NOLINT
|
|
explicit TemporaryArray(size_t n) : size_(n) { ptr_ = AllocT().allocate(n); }
|
|
TemporaryArray(size_t n, T val) : size_(n) {
|
|
ptr_ = AllocT().allocate(n);
|
|
this->fill(val);
|
|
}
|
|
~TemporaryArray() { AllocT().deallocate(ptr_, this->size()); }
|
|
void fill(T val) // NOLINT
|
|
{
|
|
int device = 0;
|
|
dh::safe_cuda(cudaGetDevice(&device));
|
|
auto d_data = ptr_.get();
|
|
LaunchN(device, this->size(), [=] __device__(size_t idx) { d_data[idx] = val; });
|
|
}
|
|
thrust::device_ptr<T> data() { return ptr_; } // NOLINT
|
|
size_t size() { return size_; } // NOLINT
|
|
|
|
private:
|
|
thrust::device_ptr<T> ptr_;
|
|
size_t size_;
|
|
};
|
|
|
|
/**
|
|
* \brief Copies device span to std::vector.
|
|
*
|
|
* \tparam T Generic type parameter.
|
|
* \param [in,out] dst Copy destination.
|
|
* \param src Copy source. Must be device memory.
|
|
*/
|
|
template <typename T>
|
|
void CopyDeviceSpanToVector(std::vector<T> *dst, xgboost::common::Span<T> src) {
|
|
CHECK_EQ(dst->size(), src.size());
|
|
dh::safe_cuda(cudaMemcpyAsync(dst->data(), src.data(), dst->size() * sizeof(T),
|
|
cudaMemcpyDeviceToHost));
|
|
}
|
|
|
|
/**
|
|
* \brief Copies const device span to std::vector.
|
|
*
|
|
* \tparam T Generic type parameter.
|
|
* \param [in,out] dst Copy destination.
|
|
* \param src Copy source. Must be device memory.
|
|
*/
|
|
template <typename T>
|
|
void CopyDeviceSpanToVector(std::vector<T> *dst, xgboost::common::Span<const T> src) {
|
|
CHECK_EQ(dst->size(), src.size());
|
|
dh::safe_cuda(cudaMemcpyAsync(dst->data(), src.data(), dst->size() * sizeof(T),
|
|
cudaMemcpyDeviceToHost));
|
|
}
|
|
|
|
template <class HContainer, class DContainer>
|
|
void CopyToD(HContainer const &h, DContainer *d) {
|
|
if (h.empty()) {
|
|
d->clear();
|
|
return;
|
|
}
|
|
d->resize(h.size());
|
|
using HVT = std::remove_cv_t<typename HContainer::value_type>;
|
|
using DVT = std::remove_cv_t<typename DContainer::value_type>;
|
|
static_assert(std::is_same<HVT, DVT>::value,
|
|
"Host and device containers must have same value type.");
|
|
dh::safe_cuda(cudaMemcpyAsync(d->data().get(), h.data(), h.size() * sizeof(HVT),
|
|
cudaMemcpyHostToDevice));
|
|
}
|
|
|
|
// Keep track of pinned memory allocation
|
|
struct PinnedMemory {
|
|
void *temp_storage{nullptr};
|
|
size_t temp_storage_bytes{0};
|
|
|
|
~PinnedMemory() { Free(); }
|
|
|
|
template <typename T>
|
|
xgboost::common::Span<T> GetSpan(size_t size) {
|
|
size_t num_bytes = size * sizeof(T);
|
|
if (num_bytes > temp_storage_bytes) {
|
|
Free();
|
|
safe_cuda(cudaMallocHost(&temp_storage, num_bytes));
|
|
temp_storage_bytes = num_bytes;
|
|
}
|
|
return xgboost::common::Span<T>(static_cast<T *>(temp_storage), size);
|
|
}
|
|
|
|
template <typename T>
|
|
xgboost::common::Span<T> GetSpan(size_t size, T init) {
|
|
auto result = this->GetSpan<T>(size);
|
|
for (auto &e : result) {
|
|
e = init;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
void Free() {
|
|
if (temp_storage != nullptr) {
|
|
safe_cuda(cudaFreeHost(temp_storage));
|
|
}
|
|
}
|
|
};
|
|
|
|
/*
|
|
* Utility functions
|
|
*/
|
|
|
|
/**
|
|
* @brief Helper function to perform device-wide sum-reduction, returns to the
|
|
* host
|
|
* @param in the input array to be reduced
|
|
* @param nVals number of elements in the input array
|
|
*/
|
|
template <typename T>
|
|
typename std::iterator_traits<T>::value_type SumReduction(T in, int nVals) {
|
|
using ValueT = typename std::iterator_traits<T>::value_type;
|
|
size_t tmpSize {0};
|
|
ValueT *dummy_out = nullptr;
|
|
dh::safe_cuda(cub::DeviceReduce::Sum(nullptr, tmpSize, in, dummy_out, nVals));
|
|
|
|
TemporaryArray<char> temp(tmpSize + sizeof(ValueT));
|
|
auto ptr = reinterpret_cast<ValueT *>(temp.data().get()) + 1;
|
|
dh::safe_cuda(cub::DeviceReduce::Sum(
|
|
reinterpret_cast<void *>(ptr), tmpSize, in,
|
|
reinterpret_cast<ValueT *>(temp.data().get()),
|
|
nVals));
|
|
ValueT sum;
|
|
dh::safe_cuda(cudaMemcpy(&sum, temp.data().get(), sizeof(ValueT),
|
|
cudaMemcpyDeviceToHost));
|
|
return sum;
|
|
}
|
|
|
|
/**
|
|
* \class AllReducer
|
|
*
|
|
* \brief All reducer class that manages its own communication group and
|
|
* streams. Must be initialised before use. If XGBoost is compiled without NCCL
|
|
* this is a dummy class that will error if used with more than one GPU.
|
|
*/
|
|
class AllReducer {
|
|
bool initialised_ {false};
|
|
size_t allreduce_bytes_ {0}; // Keep statistics of the number of bytes communicated
|
|
size_t allreduce_calls_ {0}; // Keep statistics of the number of reduce calls
|
|
#ifdef XGBOOST_USE_NCCL
|
|
ncclComm_t comm_;
|
|
cudaStream_t stream_;
|
|
int device_ordinal_;
|
|
ncclUniqueId id_;
|
|
#endif
|
|
|
|
public:
|
|
AllReducer() = default;
|
|
|
|
/**
|
|
* \brief Initialise with the desired device ordinal for this communication
|
|
* group.
|
|
*
|
|
* \param device_ordinal The device ordinal.
|
|
*/
|
|
void Init(int _device_ordinal);
|
|
|
|
~AllReducer();
|
|
|
|
/**
|
|
* \brief Allreduce. Use in exactly the same way as NCCL but without needing
|
|
* streams or comms.
|
|
*
|
|
* \param sendbuff The sendbuff.
|
|
* \param recvbuff The recvbuff.
|
|
* \param count Number of elements.
|
|
*/
|
|
|
|
void AllReduceSum(const double *sendbuff, double *recvbuff, int count) {
|
|
#ifdef XGBOOST_USE_NCCL
|
|
CHECK(initialised_);
|
|
dh::safe_cuda(cudaSetDevice(device_ordinal_));
|
|
dh::safe_nccl(ncclAllReduce(sendbuff, recvbuff, count, ncclDouble, ncclSum, comm_, stream_));
|
|
allreduce_bytes_ += count * sizeof(double);
|
|
allreduce_calls_ += 1;
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* \brief Allgather implemented as grouped calls to Broadcast. This way we can accept
|
|
* different size of data on different workers.
|
|
* \param length_bytes Size of input data in bytes.
|
|
* \param segments Size of data on each worker.
|
|
* \param recvbuf Buffer storing the result of data from all workers.
|
|
*/
|
|
void AllGather(void const* data, size_t length_bytes,
|
|
std::vector<size_t>* segments, dh::caching_device_vector<char>* recvbuf);
|
|
|
|
void AllGather(uint32_t const* data, size_t length,
|
|
dh::caching_device_vector<uint32_t>* recvbuf) {
|
|
#ifdef XGBOOST_USE_NCCL
|
|
CHECK(initialised_);
|
|
size_t world = rabit::GetWorldSize();
|
|
recvbuf->resize(length * world);
|
|
safe_nccl(ncclAllGather(data, recvbuf->data().get(), length, ncclUint32,
|
|
comm_, stream_));
|
|
#endif // XGBOOST_USE_NCCL
|
|
}
|
|
|
|
/**
|
|
* \brief Allreduce. Use in exactly the same way as NCCL but without needing
|
|
* streams or comms.
|
|
*
|
|
* \param sendbuff The sendbuff.
|
|
* \param recvbuff The recvbuff.
|
|
* \param count Number of elements.
|
|
*/
|
|
|
|
void AllReduceSum(const float *sendbuff, float *recvbuff, int count) {
|
|
#ifdef XGBOOST_USE_NCCL
|
|
CHECK(initialised_);
|
|
dh::safe_cuda(cudaSetDevice(device_ordinal_));
|
|
dh::safe_nccl(ncclAllReduce(sendbuff, recvbuff, count, ncclFloat, ncclSum, comm_, stream_));
|
|
allreduce_bytes_ += count * sizeof(float);
|
|
allreduce_calls_ += 1;
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* \brief Allreduce. Use in exactly the same way as NCCL but without needing streams or comms.
|
|
*
|
|
* \param count Number of.
|
|
*
|
|
* \param sendbuff The sendbuff.
|
|
* \param recvbuff The recvbuff.
|
|
* \param count Number of.
|
|
*/
|
|
|
|
void AllReduceSum(const int64_t *sendbuff, int64_t *recvbuff, int count) {
|
|
#ifdef XGBOOST_USE_NCCL
|
|
CHECK(initialised_);
|
|
|
|
dh::safe_cuda(cudaSetDevice(device_ordinal_));
|
|
dh::safe_nccl(ncclAllReduce(sendbuff, recvbuff, count, ncclInt64, ncclSum, comm_, stream_));
|
|
#endif
|
|
}
|
|
|
|
void AllReduceSum(const uint32_t *sendbuff, uint32_t *recvbuff, int count) {
|
|
#ifdef XGBOOST_USE_NCCL
|
|
CHECK(initialised_);
|
|
|
|
dh::safe_cuda(cudaSetDevice(device_ordinal_));
|
|
dh::safe_nccl(ncclAllReduce(sendbuff, recvbuff, count, ncclUint32, ncclSum, comm_, stream_));
|
|
#endif
|
|
}
|
|
|
|
void AllReduceSum(const uint64_t *sendbuff, uint64_t *recvbuff, int count) {
|
|
#ifdef XGBOOST_USE_NCCL
|
|
CHECK(initialised_);
|
|
|
|
dh::safe_cuda(cudaSetDevice(device_ordinal_));
|
|
dh::safe_nccl(ncclAllReduce(sendbuff, recvbuff, count, ncclUint64, ncclSum, comm_, stream_));
|
|
#endif
|
|
}
|
|
|
|
// Specialization for size_t, which is implementation defined so it might or might not
|
|
// be one of uint64_t/uint32_t/unsigned long long/unsigned long.
|
|
template <typename T = size_t,
|
|
std::enable_if_t<std::is_same<size_t, T>::value &&
|
|
!std::is_same<size_t, unsigned long long>::value> // NOLINT
|
|
* = nullptr>
|
|
void AllReduceSum(const T *sendbuff, T *recvbuff, int count) { // NOLINT
|
|
#ifdef XGBOOST_USE_NCCL
|
|
CHECK(initialised_);
|
|
|
|
dh::safe_cuda(cudaSetDevice(device_ordinal_));
|
|
static_assert(sizeof(unsigned long long) == sizeof(uint64_t), ""); // NOLINT
|
|
dh::safe_nccl(ncclAllReduce(sendbuff, recvbuff, count, ncclUint64, ncclSum, comm_, stream_));
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* \fn void Synchronize()
|
|
*
|
|
* \brief Synchronizes the entire communication group.
|
|
*/
|
|
void Synchronize() {
|
|
#ifdef XGBOOST_USE_NCCL
|
|
dh::safe_cuda(cudaSetDevice(device_ordinal_));
|
|
dh::safe_cuda(cudaStreamSynchronize(stream_));
|
|
#endif
|
|
};
|
|
|
|
#ifdef XGBOOST_USE_NCCL
|
|
/**
|
|
* \fn ncclUniqueId GetUniqueId()
|
|
*
|
|
* \brief Gets the Unique ID from NCCL to be used in setting up interprocess
|
|
* communication
|
|
*
|
|
* \return the Unique ID
|
|
*/
|
|
ncclUniqueId GetUniqueId() {
|
|
static const int kRootRank = 0;
|
|
ncclUniqueId id;
|
|
if (rabit::GetRank() == kRootRank) {
|
|
dh::safe_nccl(ncclGetUniqueId(&id));
|
|
}
|
|
rabit::Broadcast(
|
|
static_cast<void*>(&id),
|
|
sizeof(ncclUniqueId),
|
|
static_cast<int>(kRootRank));
|
|
return id;
|
|
}
|
|
#endif
|
|
};
|
|
|
|
template <typename VectorT, typename T = typename VectorT::value_type,
|
|
typename IndexT = typename xgboost::common::Span<T>::index_type>
|
|
xgboost::common::Span<T> ToSpan(
|
|
VectorT &vec,
|
|
IndexT offset = 0,
|
|
IndexT size = std::numeric_limits<size_t>::max()) {
|
|
size = size == std::numeric_limits<size_t>::max() ? vec.size() : size;
|
|
CHECK_LE(offset + size, vec.size());
|
|
return {vec.data().get() + offset, size};
|
|
}
|
|
|
|
template <typename T>
|
|
xgboost::common::Span<T> ToSpan(thrust::device_vector<T>& vec,
|
|
size_t offset, size_t size) {
|
|
return ToSpan(vec, offset, size);
|
|
}
|
|
|
|
// thrust begin, similiar to std::begin
|
|
template <typename T>
|
|
thrust::device_ptr<T> tbegin(xgboost::HostDeviceVector<T>& vector) { // NOLINT
|
|
return thrust::device_ptr<T>(vector.DevicePointer());
|
|
}
|
|
|
|
template <typename T>
|
|
thrust::device_ptr<T> tend(xgboost::HostDeviceVector<T>& vector) { // // NOLINT
|
|
return tbegin(vector) + vector.Size();
|
|
}
|
|
|
|
template <typename T>
|
|
thrust::device_ptr<T const> tcbegin(xgboost::HostDeviceVector<T> const& vector) { // NOLINT
|
|
return thrust::device_ptr<T const>(vector.ConstDevicePointer());
|
|
}
|
|
|
|
template <typename T>
|
|
thrust::device_ptr<T const> tcend(xgboost::HostDeviceVector<T> const& vector) { // NOLINT
|
|
return tcbegin(vector) + vector.Size();
|
|
}
|
|
|
|
template <typename T>
|
|
thrust::device_ptr<T> tbegin(xgboost::common::Span<T>& span) { // NOLINT
|
|
return thrust::device_ptr<T>(span.data());
|
|
}
|
|
|
|
template <typename T>
|
|
thrust::device_ptr<T> tend(xgboost::common::Span<T>& span) { // NOLINT
|
|
return tbegin(span) + span.size();
|
|
}
|
|
|
|
template <typename T>
|
|
thrust::device_ptr<T const> tcbegin(xgboost::common::Span<T> const& span) { // NOLINT
|
|
return thrust::device_ptr<T const>(span.data());
|
|
}
|
|
|
|
template <typename T>
|
|
thrust::device_ptr<T const> tcend(xgboost::common::Span<T> const& span) { // NOLINT
|
|
return tcbegin(span) + span.size();
|
|
}
|
|
|
|
// This type sorts an array which is divided into multiple groups. The sorting is influenced
|
|
// by the function object 'Comparator'
|
|
template <typename T>
|
|
class SegmentSorter {
|
|
private:
|
|
// Items sorted within the group
|
|
caching_device_vector<T> ditems_;
|
|
|
|
// Original position of the items before they are sorted descendingly within its groups
|
|
caching_device_vector<uint32_t> doriginal_pos_;
|
|
|
|
// Segments within the original list that delineates the different groups
|
|
caching_device_vector<uint32_t> group_segments_;
|
|
|
|
// Need this on the device as it is used in the kernels
|
|
caching_device_vector<uint32_t> dgroups_; // Group information on device
|
|
|
|
// Where did the item that was originally present at position 'x' move to after they are sorted
|
|
caching_device_vector<uint32_t> dindexable_sorted_pos_;
|
|
|
|
// Initialize everything but the segments
|
|
void Init(uint32_t num_elems) {
|
|
ditems_.resize(num_elems);
|
|
|
|
doriginal_pos_.resize(num_elems);
|
|
thrust::sequence(doriginal_pos_.begin(), doriginal_pos_.end());
|
|
}
|
|
|
|
// Initialize all with group info
|
|
void Init(const std::vector<uint32_t> &groups) {
|
|
uint32_t num_elems = groups.back();
|
|
this->Init(num_elems);
|
|
this->CreateGroupSegments(groups);
|
|
}
|
|
|
|
public:
|
|
// This needs to be public due to device lambda
|
|
void CreateGroupSegments(const std::vector<uint32_t> &groups) {
|
|
uint32_t num_elems = groups.back();
|
|
group_segments_.resize(num_elems, 0);
|
|
|
|
dgroups_ = groups;
|
|
|
|
if (GetNumGroups() == 1) return; // There are no segments; hence, no need to compute them
|
|
|
|
// Define the segments by assigning a group ID to each element
|
|
const uint32_t *dgroups = dgroups_.data().get();
|
|
uint32_t ngroups = dgroups_.size();
|
|
auto ComputeGroupIDLambda = [=] __device__(uint32_t idx) {
|
|
return thrust::upper_bound(thrust::seq, dgroups, dgroups + ngroups, idx) -
|
|
dgroups - 1;
|
|
}; // NOLINT
|
|
|
|
thrust::transform(thrust::make_counting_iterator(static_cast<uint32_t>(0)),
|
|
thrust::make_counting_iterator(num_elems),
|
|
group_segments_.begin(),
|
|
ComputeGroupIDLambda);
|
|
}
|
|
|
|
// Accessors that returns device pointer
|
|
inline uint32_t GetNumItems() const { return ditems_.size(); }
|
|
inline const xgboost::common::Span<const T> GetItemsSpan() const {
|
|
return { ditems_.data().get(), ditems_.size() };
|
|
}
|
|
|
|
inline const xgboost::common::Span<const uint32_t> GetOriginalPositionsSpan() const {
|
|
return { doriginal_pos_.data().get(), doriginal_pos_.size() };
|
|
}
|
|
|
|
inline const xgboost::common::Span<const uint32_t> GetGroupSegmentsSpan() const {
|
|
return { group_segments_.data().get(), group_segments_.size() };
|
|
}
|
|
|
|
inline uint32_t GetNumGroups() const { return dgroups_.size() - 1; }
|
|
inline const xgboost::common::Span<const uint32_t> GetGroupsSpan() const {
|
|
return { dgroups_.data().get(), dgroups_.size() };
|
|
}
|
|
|
|
inline const xgboost::common::Span<const uint32_t> GetIndexableSortedPositionsSpan() const {
|
|
return { dindexable_sorted_pos_.data().get(), dindexable_sorted_pos_.size() };
|
|
}
|
|
|
|
// Sort an array that is divided into multiple groups. The array is sorted within each group.
|
|
// This version provides the group information that is on the host.
|
|
// The array is sorted based on an adaptable binary predicate. By default a stateless predicate
|
|
// is used.
|
|
template <typename Comparator = thrust::greater<T>>
|
|
void SortItems(const T *ditems, uint32_t item_size, const std::vector<uint32_t> &groups,
|
|
const Comparator &comp = Comparator()) {
|
|
this->Init(groups);
|
|
this->SortItems(ditems, item_size, this->GetGroupSegmentsSpan(), comp);
|
|
}
|
|
|
|
// Sort an array that is divided into multiple groups. The array is sorted within each group.
|
|
// This version provides the group information that is on the device.
|
|
// The array is sorted based on an adaptable binary predicate. By default a stateless predicate
|
|
// is used.
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template <typename Comparator = thrust::greater<T>>
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void SortItems(const T *ditems, uint32_t item_size,
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const xgboost::common::Span<const uint32_t> &group_segments,
|
|
const Comparator &comp = Comparator()) {
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this->Init(item_size);
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|
|
|
// Sort the items that are grouped. We would like to avoid using predicates to perform the sort,
|
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// as thrust resorts to using a merge sort as opposed to a much much faster radix sort
|
|
// when comparators are used. Hence, the following algorithm is used. This is done so that
|
|
// we can grab the appropriate related values from the original list later, after the
|
|
// items are sorted.
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|
//
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|
// Here is the internal representation:
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// dgroups_: [ 0, 3, 5, 8, 10 ]
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// group_segments_: 0 0 0 | 1 1 | 2 2 2 | 3 3
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// doriginal_pos_: 0 1 2 | 3 4 | 5 6 7 | 8 9
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// ditems_: 1 0 1 | 2 1 | 1 3 3 | 4 4 (from original items)
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//
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|
// Sort the items first and make a note of the original positions in doriginal_pos_
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|
// based on the sort
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|
// ditems_: 4 4 3 3 2 1 1 1 1 0
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|
// doriginal_pos_: 8 9 6 7 3 0 2 4 5 1
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// NOTE: This consumes space, but is much faster than some of the other approaches - sorting
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|
// in kernel, sorting using predicates etc.
|
|
|
|
ditems_.assign(thrust::device_ptr<const T>(ditems),
|
|
thrust::device_ptr<const T>(ditems) + item_size);
|
|
|
|
// Allocator to be used by sort for managing space overhead while sorting
|
|
dh::XGBCachingDeviceAllocator<char> alloc;
|
|
|
|
thrust::stable_sort_by_key(thrust::cuda::par(alloc),
|
|
ditems_.begin(), ditems_.end(),
|
|
doriginal_pos_.begin(), comp);
|
|
|
|
if (GetNumGroups() == 1) return; // The entire array is sorted, as it isn't segmented
|
|
|
|
// Next, gather the segments based on the doriginal_pos_. This is to reflect the
|
|
// holisitic item sort order on the segments
|
|
// group_segments_c_: 3 3 2 2 1 0 0 1 2 0
|
|
// doriginal_pos_: 8 9 6 7 3 0 2 4 5 1 (stays the same)
|
|
caching_device_vector<uint32_t> group_segments_c(item_size);
|
|
thrust::gather(doriginal_pos_.begin(), doriginal_pos_.end(),
|
|
dh::tcbegin(group_segments), group_segments_c.begin());
|
|
|
|
// Now, sort the group segments so that you may bring the items within the group together,
|
|
// in the process also noting the relative changes to the doriginal_pos_ while that happens
|
|
// group_segments_c_: 0 0 0 1 1 2 2 2 3 3
|
|
// doriginal_pos_: 0 2 1 3 4 6 7 5 8 9
|
|
thrust::stable_sort_by_key(thrust::cuda::par(alloc),
|
|
group_segments_c.begin(), group_segments_c.end(),
|
|
doriginal_pos_.begin(), thrust::less<uint32_t>());
|
|
|
|
// Finally, gather the original items based on doriginal_pos_ to sort the input and
|
|
// to store them in ditems_
|
|
// doriginal_pos_: 0 2 1 3 4 6 7 5 8 9 (stays the same)
|
|
// ditems_: 1 1 0 2 1 3 3 1 4 4 (from unsorted items - ditems)
|
|
thrust::gather(doriginal_pos_.begin(), doriginal_pos_.end(),
|
|
thrust::device_ptr<const T>(ditems), ditems_.begin());
|
|
}
|
|
|
|
// Determine where an item that was originally present at position 'x' has been relocated to
|
|
// after a sort. Creation of such an index has to be explicitly requested after a sort
|
|
void CreateIndexableSortedPositions() {
|
|
dindexable_sorted_pos_.resize(GetNumItems());
|
|
thrust::scatter(thrust::make_counting_iterator(static_cast<uint32_t>(0)),
|
|
thrust::make_counting_iterator(GetNumItems()), // Rearrange indices...
|
|
// ...based on this map
|
|
dh::tcbegin(GetOriginalPositionsSpan()),
|
|
dindexable_sorted_pos_.begin()); // Write results into this
|
|
}
|
|
};
|
|
|
|
// Atomic add function for gradients
|
|
template <typename OutputGradientT, typename InputGradientT>
|
|
XGBOOST_DEV_INLINE void AtomicAddGpair(OutputGradientT* dest,
|
|
const InputGradientT& gpair) {
|
|
auto dst_ptr = reinterpret_cast<typename OutputGradientT::ValueT*>(dest);
|
|
|
|
atomicAdd(dst_ptr,
|
|
static_cast<typename OutputGradientT::ValueT>(gpair.GetGrad()));
|
|
atomicAdd(dst_ptr + 1,
|
|
static_cast<typename OutputGradientT::ValueT>(gpair.GetHess()));
|
|
}
|
|
|
|
|
|
// Thrust version of this function causes error on Windows
|
|
template <typename ReturnT, typename IterT, typename FuncT>
|
|
XGBOOST_DEVICE thrust::transform_iterator<FuncT, IterT, ReturnT> MakeTransformIterator(
|
|
IterT iter, FuncT func) {
|
|
return thrust::transform_iterator<FuncT, IterT, ReturnT>(iter, func);
|
|
}
|
|
|
|
template <typename It>
|
|
size_t XGBOOST_DEVICE SegmentId(It first, It last, size_t idx) {
|
|
size_t segment_id = thrust::upper_bound(thrust::seq, first, last, idx) -
|
|
1 - first;
|
|
return segment_id;
|
|
}
|
|
|
|
template <typename T>
|
|
size_t XGBOOST_DEVICE SegmentId(xgboost::common::Span<T> segments_ptr, size_t idx) {
|
|
return SegmentId(segments_ptr.cbegin(), segments_ptr.cend(), idx);
|
|
}
|
|
|
|
namespace detail {
|
|
template <typename Key, typename KeyOutIt>
|
|
struct SegmentedUniqueReduceOp {
|
|
KeyOutIt key_out;
|
|
__device__ Key const& operator()(Key const& key) const {
|
|
auto constexpr kOne = static_cast<std::remove_reference_t<decltype(*(key_out + key.first))>>(1);
|
|
atomicAdd(&(*(key_out + key.first)), kOne);
|
|
return key;
|
|
}
|
|
};
|
|
} // namespace detail
|
|
|
|
/* \brief Segmented unique function. Keys are pointers to segments with key_segments_last -
|
|
* key_segments_first = n_segments + 1.
|
|
*
|
|
* \pre Input segment and output segment must not overlap.
|
|
*
|
|
* \param key_segments_first Beginning iterator of segments.
|
|
* \param key_segments_last End iterator of segments.
|
|
* \param val_first Beginning iterator of values.
|
|
* \param val_last End iterator of values.
|
|
* \param key_segments_out Output iterator of segments.
|
|
* \param val_out Output iterator of values.
|
|
*
|
|
* \return Number of unique values in total.
|
|
*/
|
|
template <typename KeyInIt, typename KeyOutIt, typename ValInIt,
|
|
typename ValOutIt, typename Comp>
|
|
size_t
|
|
SegmentedUnique(KeyInIt key_segments_first, KeyInIt key_segments_last, ValInIt val_first,
|
|
ValInIt val_last, KeyOutIt key_segments_out, ValOutIt val_out,
|
|
Comp comp) {
|
|
using Key = thrust::pair<size_t, typename thrust::iterator_traits<ValInIt>::value_type>;
|
|
dh::XGBCachingDeviceAllocator<char> alloc;
|
|
auto unique_key_it = dh::MakeTransformIterator<Key>(
|
|
thrust::make_counting_iterator(static_cast<size_t>(0)),
|
|
[=] __device__(size_t i) {
|
|
size_t seg = dh::SegmentId(key_segments_first, key_segments_last, i);
|
|
return thrust::make_pair(seg, *(val_first + i));
|
|
});
|
|
size_t segments_len = key_segments_last - key_segments_first;
|
|
thrust::fill(thrust::device, key_segments_out, key_segments_out + segments_len, 0);
|
|
size_t n_inputs = std::distance(val_first, val_last);
|
|
// Reduce the number of uniques elements per segment, avoid creating an intermediate
|
|
// array for `reduce_by_key`. It's limited by the types that atomicAdd supports. For
|
|
// example, size_t is not supported as of CUDA 10.2.
|
|
auto reduce_it = thrust::make_transform_output_iterator(
|
|
thrust::make_discard_iterator(),
|
|
detail::SegmentedUniqueReduceOp<Key, KeyOutIt>{key_segments_out});
|
|
auto uniques_ret = thrust::unique_by_key_copy(
|
|
thrust::cuda::par(alloc), unique_key_it, unique_key_it + n_inputs,
|
|
val_first, reduce_it, val_out,
|
|
[=] __device__(Key const &l, Key const &r) {
|
|
if (l.first == r.first) {
|
|
// In the same segment.
|
|
return comp(l.second, r.second);
|
|
}
|
|
return false;
|
|
});
|
|
auto n_uniques = uniques_ret.second - val_out;
|
|
CHECK_LE(n_uniques, n_inputs);
|
|
thrust::exclusive_scan(thrust::cuda::par(alloc), key_segments_out,
|
|
key_segments_out + segments_len, key_segments_out, 0);
|
|
return n_uniques;
|
|
}
|
|
} // namespace dh
|