Simplify size op impl (#45808)

* simplify size op

* trans to cuda manuly

* fix copy error

paddle/phi/kernels/cpu/size_kernel.cc

-// Copyright (c) 2022 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/size_kernel.h"
-
-#include "paddle/phi/backends/cpu/cpu_context.h"
-#include "paddle/phi/core/kernel_registry.h"
-#include "paddle/phi/kernels/impl/size_kernel_impl.h"
-
-PD_REGISTER_KERNEL(size,
-                   CPU,
-                   ALL_LAYOUT,
-                   phi::SizeKernel,
-                   uint8_t,
-                   int16_t,
-                   int,
-                   int64_t,
-                   phi::dtype::float16,
-                   float,
-                   double,
-                   bool) {}

paddle/phi/kernels/gpu/size_kernel.cu

-// Copyright (c) 2022 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/size_kernel.h"
-
-#include "paddle/phi/backends/gpu/gpu_context.h"
-#include "paddle/phi/core/kernel_registry.h"
-#include "paddle/phi/kernels/impl/size_kernel_impl.h"
-
-PD_REGISTER_KERNEL(size,
-                   GPU,
-                   ALL_LAYOUT,
-                   phi::SizeKernel,
-                   int16_t,
-                   int,
-                   int64_t,
-                   phi::dtype::float16,
-                   float,
-                   double,
-                   bool) {}

paddle/phi/kernels/impl/size_kernel_impl.h → paddle/phi/kernels/size_kernel.cc

@@ -12,28 +12,33 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#pragma once
+#include "paddle/phi/kernels/size_kernel.h"
 
+#include "paddle/phi/core/kernel_registry.h"
 #include "paddle/phi/core/tensor_utils.h"
 
 namespace phi {
 
-template <typename T, typename Context>
+template <typename Context>
 void SizeKernel(const Context& ctx,
                 const DenseTensor& input,
                 DenseTensor* out) {
-  auto place = ctx.GetPlace();
-  auto out_data = ctx.template Alloc<int64_t>(out);
-  auto cpu_place = phi::CPUPlace();
-  if (place == cpu_place) {
+  auto* out_data = ctx.template HostAlloc<int64_t>(out);
   out_data[0] = input.numel();
-  } else {
-    DenseTensor cpu_tensor;
-    cpu_tensor.Resize(out->dims());
-    auto cpu_data = ctx.template HostAlloc<int64_t>(&cpu_tensor);
-    cpu_data[0] = input.numel();
-    phi::Copy(ctx, cpu_tensor, place, false, out);
-  }
 }
 
 }  // namespace phi
+
+PD_REGISTER_GENERAL_KERNEL(
+    size, CPU, ALL_LAYOUT, phi::SizeKernel<phi::CPUContext>, ALL_DTYPE) {
+  kernel->OutputAt(0).SetDataType(phi::DataType::INT64);
+}
+
+#if defined(PADDLE_WITH_CUDA) || defined(PADDLE_WITH_HIP)
+PD_REGISTER_GENERAL_KERNEL(
+    size, GPU, ALL_LAYOUT, phi::SizeKernel<phi::GPUContext>, ALL_DTYPE) {
+  kernel->OutputAt(0)
+      .SetBackend(phi::Backend::CPU)
+      .SetDataType(phi::DataType::INT64);
+}
+#endif

paddle/phi/kernels/size_kernel.h

@@ -18,7 +18,7 @@
 
 namespace phi {
 
-template <typename T, typename Context>
+template <typename Context>
 void SizeKernel(const Context& ctx, const DenseTensor& input, DenseTensor* out);
 
 }  // namespace phi

python/paddle/distributed/collective.py

@@ -1140,6 +1140,9 @@ def all_gather_object(object_list, obj, group=None):
     ), "all_gather_object doesn't support static graph mode."
 
     tensor, len_of_tensor = _convert_object_to_tensor(obj)
+    if paddle.get_device() != "cpu":
+        len_of_tensor = len_of_tensor._copy_to(
+            paddle.framework._current_expected_place(), False)
 
     # gather len_of_tensor from all ranks
     list_len_of_tensor = []