// Copyright (c) 2024 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "paddle/phi/kernels/barrier_kernel.h"
#include "paddle/phi/core/dense_tensor.h"
#include "paddle/phi/core/kernel_registry.h"
#if defined(PADDLE_WITH_NCCL) || defined(PADDLE_WITH_RCCL)
#include "paddle/phi/core/distributed/nccl_comm_context.h"
#endif

namespace phi {

template <typename T, typename Context>
void BarrierKernel(const Context &dev_ctx,
                   const DenseTensor &x,
                   DenseTensor *out) {
#if defined(PADDLE_WITH_NCCL) || defined(PADDLE_WITH_RCCL)
  auto in = &x;
  auto comm_ctx =
      static_cast<distributed::NCCLCommContext *>(dev_ctx.GetCommContext());
  PADDLE_ENFORCE_NE(comm_ctx,
                    nullptr,
                    common::errors::Unavailable(
                        "NCCLCommContext is nullptr, collective op should "
                        "has ring_id attr."));
  auto stream = comm_ctx->GetStream();
  ncclRedOp_t nccl_red_type = ncclSum;
  comm_ctx->AllReduce(out, *in, nccl_red_type, stream);
  backends::gpu::GpuStreamSync(stream);
#else
  PADDLE_THROW(
      common::errors::Unavailable("PaddlePaddle should compile with NCCL."));
#endif
}
}  // namespace phi

PD_REGISTER_KERNEL(barrier, GPU, ALL_LAYOUT, phi::BarrierKernel, int) {}