Files
DeepSpeed/csrc/lion/multi_tensor_lion.cu
Hongjiu "Enneamer" Zhang 8e64c3b550 feat: add Lion optimizer (#4331)
Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>
2023-10-05 22:32:14 +00:00

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// Copyright (c) Microsoft Corporation.
// SPDX-License-Identifier: Apache-2.0
// DeepSpeed Team
/*
Copyright NVIDIA/apex
This file is adapted from fused adam in NVIDIA/apex, commit a109f85
*/
#include <ATen/ATen.h>
#include <ATen/AccumulateType.h>
#include <ATen/cuda/CUDAContext.h>
#include <ATen/cuda/Exceptions.h>
// Another possibility:
// #include <torch/all.h>
#include <assert.h>
#include "multi_tensor_apply.cuh"
#include "type_shim.h"
#define BLOCK_SIZE 512
#define ILP 4
using MATH_T = float;
template <typename T>
struct LionFunctor {
__device__ __forceinline__ void operator()(int chunk_size,
volatile int* noop_gmem,
TensorListMetadata<3>& tl,
const float beta1,
const float beta2,
const float lr,
const float decay)
{
// I'd like this kernel to propagate infs/nans.
// if(*noop_gmem == 1)
// return;
int tensor_loc = tl.block_to_tensor[blockIdx.x];
// potentially use to pass in list of scalar
// int tensor_num = tl.start_tensor_this_launch + tensor_loc;
int chunk_idx = tl.block_to_chunk[blockIdx.x];
int n = tl.sizes[tensor_loc];
T* g = (T*)tl.addresses[0][tensor_loc];
g += chunk_idx * chunk_size;
T* p = (T*)tl.addresses[1][tensor_loc];
p += chunk_idx * chunk_size;
T* m = (T*)tl.addresses[2][tensor_loc];
m += chunk_idx * chunk_size;
n -= chunk_idx * chunk_size;
MATH_T after_decay = 1.0f - lr * decay;
// see note in multi_tensor_scale_kernel.cu
for (int i_start = 0; i_start < n && i_start < chunk_size; i_start += blockDim.x * ILP) {
MATH_T r_g[ILP];
MATH_T r_p[ILP];
MATH_T r_m[ILP];
#pragma unroll
for (int ii = 0; ii < ILP; ii++) {
int i = i_start + threadIdx.x + ii * blockDim.x;
if (i < n && i < chunk_size) {
r_g[ii] = g[i];
r_p[ii] = p[i];
r_m[ii] = m[i];
} else {
r_g[ii] = MATH_T(0);
r_p[ii] = MATH_T(0);
r_m[ii] = MATH_T(0);
}
}
#pragma unroll
for (int ii = 0; ii < ILP; ii++) {
MATH_T c = beta1 * r_m[ii] + (1 - beta1) * r_g[ii];
MATH_T update = c > 0 ? (-lr) : lr;
r_p[ii] = r_p[ii] * after_decay + update;
r_m[ii] = beta2 * r_m[ii] + (1 - beta2) * r_g[ii];
}
#pragma unroll
for (int ii = 0; ii < ILP; ii++) {
int i = i_start + threadIdx.x + ii * blockDim.x;
if (i < n && i < chunk_size) {
p[i] = r_p[ii];
m[i] = r_m[ii];
}
}
}
}
};
void multi_tensor_lion_cuda(int chunk_size,
at::Tensor noop_flag,
std::vector<std::vector<at::Tensor>> tensor_lists,
const float lr,
const float beta1,
const float beta2,
const int step,
const float weight_decay)
{
using namespace at;
// Assume single type across p,g,m1,m2 now
DISPATCH_DOUBLE_FLOAT_AND_HALF(tensor_lists[0][0].scalar_type(),
0,
"lion",
multi_tensor_apply<3>(BLOCK_SIZE,
chunk_size,
noop_flag,
tensor_lists,
LionFunctor<scalar_t_0>(),
beta1,
beta2,
lr,
weight_decay);)
AT_CUDA_CHECK(cudaGetLastError());
}