Files
pytorch/torch/csrc/distributed/c10d/Functional.cpp
2024-04-04 13:22:22 +00:00

365 lines
12 KiB
C++

#include <shared_mutex>
#include <ATen/ATen.h>
#include <ATen/core/op_registration/op_registration.h>
#include <c10/core/DispatchKey.h>
#include <torch/csrc/autograd/function.h>
#include <torch/csrc/distributed/c10d/GroupRegistry.hpp>
#include <torch/csrc/distributed/c10d/ProcessGroup.hpp>
#include <torch/csrc/distributed/c10d/RankLocal.hpp>
namespace {
class WorkRegistry {
public:
void register_work(
const at::Tensor& tensor,
c10::intrusive_ptr<c10d::Work> work) {
const auto storage = tensor.storage().getWeakStorageImpl();
std::unique_lock lock(lock_);
auto [it, inserted] = registry_.emplace(storage, work);
TORCH_CHECK(
inserted || it->second != work,
"The tensor storage is already associated with another work.");
}
c10::intrusive_ptr<c10d::Work> pop_work(const at::Tensor& tensor) {
const auto storage = tensor.storage().getWeakStorageImpl();
std::unique_lock lock(lock_);
auto it = registry_.find(storage);
if (it == registry_.end()) {
return nullptr;
}
auto work = it->second;
registry_.erase(it);
return work;
}
~WorkRegistry() {
// If there are still unwaited work objects, their corresponding process
// groups should have already been destroyed at this stage. Any attempts to
// wait for these work objects or to destroy them will only result in
// confusing errors. Therefore, we simply issue a warning and intentionally
// allow the unwaited work objects to leak.
if (!registry_.empty()) {
TORCH_WARN(
"At the time of process termination, there are still ",
registry_.size(),
" unwaited c10d_functional collective calls. "
"Please review your program to ensure c10d_functional.wait_tensor() "
"is invoked on all tensors returned from c10d_functional collective "
"ops before they are used.");
}
for (auto it = registry_.begin(); it != registry_.end(); ++it) {
it->second.release();
}
}
private:
std::unordered_map<
c10::weak_intrusive_ptr<c10::StorageImpl>,
c10::intrusive_ptr<c10d::Work>>
registry_;
std::mutex lock_;
};
static WorkRegistry process_registry;
void register_work(
const at::Tensor& tensor,
c10::intrusive_ptr<c10d::Work> work) {
if (c10d::get_thread_isolation_mode()) {
c10d::RankLocal<WorkRegistry>::get().register_work(tensor, work);
} else {
process_registry.register_work(tensor, work);
}
}
c10::intrusive_ptr<c10d::Work> pop_work(const at::Tensor& tensor) {
if (c10d::get_thread_isolation_mode()) {
return c10d::RankLocal<WorkRegistry>::get().pop_work(tensor);
} else {
return process_registry.pop_work(tensor);
}
}
const std::unordered_map<std::string, c10d::ReduceOp> str_to_reduce_op = {
{"sum", c10d::ReduceOp(c10d::ReduceOp::RedOpType::SUM)},
{"avg", c10d::ReduceOp(c10d::ReduceOp::RedOpType::AVG)},
{"product", c10d::ReduceOp(c10d::ReduceOp::RedOpType::PRODUCT)},
{"min", c10d::ReduceOp(c10d::ReduceOp::RedOpType::MIN)},
{"max", c10d::ReduceOp(c10d::ReduceOp::RedOpType::MAX)},
{"band", c10d::ReduceOp(c10d::ReduceOp::RedOpType::BAND)},
{"bor", c10d::ReduceOp(c10d::ReduceOp::RedOpType::BOR)},
{"bxor", c10d::ReduceOp(c10d::ReduceOp::RedOpType::BXOR)},
// TODO: support premul_sum
// {"premul_sum", c10d::ReduceOp(c10d::ReduceOp::RedOpType::PREMUL_SUM)},
{"unused", c10d::ReduceOp(c10d::ReduceOp::RedOpType::UNUSED)}};
c10d::ReduceOp to_reduce_op(const std::string& reduce_op) {
auto it = str_to_reduce_op.find(reduce_op);
TORCH_CHECK(
it != str_to_reduce_op.end(), "Unrecognized reduce_op: ", reduce_op);
return it->second;
}
at::Tensor& all_reduce_(
at::Tensor& input,
std::string reduce_op,
std::string group_name) {
c10d::AllreduceOptions opts;
opts.reduceOp = to_reduce_op(reduce_op);
std::vector<at::Tensor> inputs{input};
auto group = c10d::resolve_process_group(group_name);
auto work = group->allreduce(inputs, opts);
c10d::RankLocal<WorkRegistry>::get().register_work(input, work);
return input;
}
at::Tensor all_reduce(
const at::Tensor& input,
std::string reduce_op,
std::string group_name) {
auto output = input.clone(at::MemoryFormat::Contiguous);
return all_reduce_(output, reduce_op, group_name);
}
std::vector<at::Tensor> all_reduce_coalesced_(
std::vector<at::Tensor> inputs,
std::string reduce_op,
std::string group_name) {
c10d::AllreduceCoalescedOptions opts;
opts.reduceOp = to_reduce_op(reduce_op);
auto group = c10d::resolve_process_group(group_name);
auto work = group->allreduce_coalesced(inputs, opts);
for (const auto& tensor : inputs) {
c10d::RankLocal<WorkRegistry>::get().register_work(tensor, work);
}
return inputs;
}
std::vector<at::Tensor> all_reduce_coalesced(
std::vector<at::Tensor> inputs,
std::string reduce_op,
std::string group_name) {
std::vector<at::Tensor> outputs;
outputs.reserve(inputs.size());
for (const auto& tensor : inputs) {
outputs.push_back(tensor.clone(at::MemoryFormat::Contiguous));
}
return all_reduce_coalesced_(outputs, reduce_op, group_name);
}
at::Tensor allocate_all_gather_output(
const at::Tensor& input,
int64_t group_size) {
auto output_size = input.sizes().vec();
output_size[0] *= group_size;
return at::empty(
output_size,
at::TensorOptions().dtype(input.dtype()).device(input.device()));
}
std::vector<at::Tensor> all_gather_into_tensor_coalesced(
std::vector<at::Tensor> inputs,
int64_t group_size,
std::string group_name) {
std::vector<at::Tensor> outputs;
for (const auto& tensor : inputs) {
outputs.push_back(allocate_all_gather_output(tensor, group_size));
}
auto group = c10d::resolve_process_group(group_name);
auto work = group->allgather_into_tensor_coalesced(
outputs, const_cast<std::vector<at::Tensor>&>(inputs));
for (const auto& tensor : outputs) {
c10d::RankLocal<WorkRegistry>::get().register_work(tensor, work);
}
return outputs;
}
at::Tensor all_gather_into_tensor(
const at::Tensor& input,
int64_t group_size,
std::string group_name) {
std::vector<at::Tensor> inputs{input};
return all_gather_into_tensor_coalesced(inputs, group_size, group_name)[0];
}
at::Tensor allocate_reduce_scatter_output(
const at::Tensor& input,
const int64_t group_size) {
auto output_size = input.sizes().vec();
if (output_size[0] % group_size != 0) {
LOG(WARNING) << "The first dimension of the reduce_scatter input ("
<< output_size[0] << ") is not divisible by the group size ("
<< group_size << ").";
}
output_size[0] /= group_size;
return at::empty(
output_size,
at::TensorOptions().dtype(input.dtype()).device(input.device()));
}
std::vector<at::Tensor> reduce_scatter_tensor_coalesced(
std::vector<at::Tensor> inputs,
std::string reduce_op,
int64_t group_size,
std::string group_name) {
c10d::ReduceScatterOptions opts;
opts.reduceOp = to_reduce_op(reduce_op);
std::vector<at::Tensor> outputs;
for (const auto& tensor : inputs) {
outputs.push_back(allocate_reduce_scatter_output(tensor, group_size));
}
auto group = c10d::resolve_process_group(group_name);
auto work = group->reduce_scatter_tensor_coalesced(
outputs, const_cast<std::vector<at::Tensor>&>(inputs), opts);
for (const auto& tensor : outputs) {
c10d::RankLocal<WorkRegistry>::get().register_work(tensor, work);
}
return outputs;
}
at::Tensor reduce_scatter_tensor(
const at::Tensor& input,
std::string reduce_op,
int64_t group_size,
std::string group_name) {
std::vector<at::Tensor> inputs{input};
return reduce_scatter_tensor_coalesced(
inputs, reduce_op, group_size, group_name)[0];
}
at::Tensor all_to_all_single(
const at::Tensor& input,
std::vector<int64_t> output_split_sizes,
std::vector<int64_t> input_split_sizes,
std::string group_name) {
std::vector<int64_t> output_sizes = input.sizes().vec();
output_sizes[0] =
std::accumulate(output_split_sizes.begin(), output_split_sizes.end(), 0);
auto output = input.new_empty(output_sizes);
auto group = c10d::resolve_process_group(group_name);
auto work = group->alltoall_base(
output,
const_cast<at::Tensor&>(input),
output_split_sizes,
input_split_sizes);
c10d::RankLocal<WorkRegistry>::get().register_work(output, work);
return output;
}
at::Tensor& broadcast_(at::Tensor& input, int64_t src, std::string group_name) {
c10d::BroadcastOptions opts;
opts.rootRank = src;
std::vector<at::Tensor> inputs{input};
auto group = c10d::resolve_process_group(group_name);
auto work = group->broadcast(inputs, opts);
c10d::RankLocal<WorkRegistry>::get().register_work(input, work);
return input;
}
at::Tensor broadcast(
const at::Tensor& input,
int64_t src,
std::string group_name) {
auto output = input.clone(at::MemoryFormat::Contiguous);
return broadcast_(output, src, group_name);
}
at::Tensor wait_tensor(const at::Tensor& tensor) {
auto work = c10d::RankLocal<WorkRegistry>::get().pop_work(tensor);
if (work != nullptr) {
work->wait();
}
return tensor;
}
} // namespace
TORCH_LIBRARY(_c10d_functional, m) {
m.def(
"all_reduce(Tensor input, str reduce_op, str group_name) -> Tensor",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::all_reduce),
{at::Tag::pt2_compliant_tag});
m.def(
"all_reduce_(Tensor(a!) input, str reduce_op, str group_name) -> Tensor(a!)",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::all_reduce_),
{at::Tag::pt2_compliant_tag});
m.def(
"all_reduce_coalesced(Tensor[] inputs, str reduce_op, str group_name) -> Tensor[]",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::all_reduce_coalesced),
{at::Tag::pt2_compliant_tag});
m.def(
"all_reduce_coalesced_(Tensor[](a!) inputs, str reduce_op, str group_name) -> Tensor[](a!)",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::all_reduce_coalesced_),
{at::Tag::pt2_compliant_tag});
m.def(
"all_gather_into_tensor(Tensor input, int group_size, str group_name) -> Tensor",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd,
::all_gather_into_tensor),
{at::Tag::pt2_compliant_tag});
m.def(
"all_gather_into_tensor_coalesced(Tensor[] inputs, int group_size, str group_name) -> Tensor[]",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd,
::all_gather_into_tensor_coalesced),
{at::Tag::pt2_compliant_tag});
m.def(
"reduce_scatter_tensor(Tensor input, str reduce_op, int group_size, str group_name) -> Tensor",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::reduce_scatter_tensor),
{at::Tag::pt2_compliant_tag});
m.def(
"reduce_scatter_tensor_coalesced(Tensor[] inputs, str reduce_op, int group_size, str group_name) -> Tensor[]",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd,
::reduce_scatter_tensor_coalesced),
{at::Tag::pt2_compliant_tag});
m.def(
"all_to_all_single("
"Tensor input, "
"SymInt[] output_split_sizes, "
"SymInt[] input_split_sizes, "
"str group_name) -> Tensor",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::all_to_all_single),
{at::Tag::pt2_compliant_tag});
m.def(
"broadcast(Tensor input, int src, str group_name) -> Tensor",
torch::dispatch(c10::DispatchKey::CompositeExplicitAutograd, ::broadcast),
{at::Tag::pt2_compliant_tag});
m.def(
"broadcast_(Tensor(a!) input, int src, str group_name) -> Tensor(a!)",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::broadcast_),
{at::Tag::pt2_compliant_tag});
m.def(
"wait_tensor(Tensor tensor) -> Tensor",
torch::dispatch(
c10::DispatchKey::CompositeExplicitAutograd, ::wait_tensor),
{at::Tag::pt2_compliant_tag});
}