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Composable Kernel: /home/docs/checkouts/readthedocs.org/user_builds/advanced-micro-devices-composable-kernel/checkouts/develop/include/ck_tile/ops/topk_softmax/kernel/topk_softmax_kernel.hpp Source File

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 // SPDX-License-Identifier: MIT
 // Copyright (c) 2018-2025, Advanced Micro Devices, Inc. All rights reserved.
  
 #pragma once
  
 #include "ck_tile/core.hpp"
 #include "ck_tile/ops/common.hpp"
 #include "ck_tile/ops/elementwise.hpp"
 #include "ck_tile/host/hip_check_error.hpp"
 #include <string>
 #include <type_traits>
  
 namespace ck_tile {
  
 struct TopkSoftmaxHostArgs
 {
     const void* p_input;
     void* p_output;
     void* p_indices;
     index_t num_rows;
     index_t num_experts;
     index_t topk;
     index_t stride_input;  // row stride for input, at least experts
     index_t stride_output; // row stride for output/indices, at least tpok
 };
  
 template <typename Pipeline_>
 struct TopkSoftmaxKernel
 {
     using Pipeline = remove_cvref_t<Pipeline_>;
     using Problem  = remove_cvref_t<typename Pipeline::Problem>;
  
     using InputType  = typename Problem::InputType;
     using WeightType = typename Problem::WeightType;
     using IndexType  = typename Problem::IndexType;
  
     static constexpr index_t kBlockSize = Problem::BlockSize;
  
     struct TopkSoftmaxKargs
     {
         const void* p_input;
         void* p_output;
         void* p_indices;
         index_t num_rows;
         index_t num_experts;
         index_t topk;
         index_t stride_input;  // row stride for input, at least experts
         index_t stride_output; // row stride for output/indices, at least tpok
     };
  
     using Kargs = TopkSoftmaxKargs;
     using Hargs = TopkSoftmaxHostArgs;
  
     CK_TILE_HOST static constexpr auto GridSize(const Hargs& h)
     {
         if constexpr(Problem::LaunchType > 0)
         {
             int num_cu = [&]() {
                 hipDeviceProp_t dev_prop;
                 hipDevice_t dev;
                 HIP_CHECK_ERROR(hipGetDevice(&dev));
                 HIP_CHECK_ERROR(hipGetDeviceProperties(&dev_prop, dev));
                 return dev_prop.multiProcessorCount;
             }();
             return dim3(num_cu * Problem::LaunchType);
         }
         else
         {
             const int num_warps = (h.num_rows + Problem::RowsPerWarp - 1) / Problem::RowsPerWarp;
             const int num_blocks =
                 (num_warps + Problem::WarpsPerBlock - 1) / Problem::WarpsPerBlock;
             return dim3(num_blocks);
         }
     }
  
     CK_TILE_HOST static constexpr auto MakeKargs(const Hargs& h)
     {
         Kargs k;
         k.p_input       = h.p_input;
         k.p_output      = h.p_output;
         k.p_indices     = h.p_indices;
         k.num_rows      = h.num_rows;
         k.num_experts   = h.num_experts;
         k.topk          = h.topk;
         k.stride_input  = h.stride_input;
         k.stride_output = h.stride_output;
         return k;
     }
  
     CK_TILE_HOST_DEVICE static constexpr auto BlockSize() { return Problem::BlockSize; }
  
     CK_TILE_DEVICE void operator()(Kargs kargs) const
     {
         index_t block_row_id = static_cast<index_t>(blockIdx.x * Problem::RowsPerBlock);
  
         if(block_row_id > kargs.num_rows)
             return;
  
         index_t block_os_inp = __builtin_amdgcn_readfirstlane(block_row_id * kargs.stride_input);
         index_t block_os_out = __builtin_amdgcn_readfirstlane(block_row_id * kargs.stride_output);
         index_t num_rows_rem = __builtin_amdgcn_readfirstlane(kargs.num_rows - block_row_id);
  
         const auto input_window = [&]() {
             const InputType* p_input =
                 reinterpret_cast<const InputType*>(kargs.p_input) + block_os_inp;
  
             auto tmp = make_naive_tensor_view<address_space_enum::global>(
                 p_input,
                 make_tuple(num_rows_rem, kargs.num_experts),
                 make_tuple(kargs.stride_input, 1),
                 number<Problem::VectorSize>{},
                 number<1>{});
  
             auto view = pad_tensor_view(
                 tmp,
                 make_tuple(number<Problem::RowsPerBlock>{}, number<Problem::Experts>{}),
                 sequence<0, 1>{}); // out-most dim no need pad(leverage oob)
  
             return make_tile_window(
                 view,
                 make_tuple(number<Problem::RowsPerBlock>{}, number<Problem::Experts>{}),
                 {0, 0});
         }();
  
         auto output_window = [&]() {
             WeightType* p_output = reinterpret_cast<WeightType*>(kargs.p_output) + block_os_out;
             auto tmp             = make_naive_tensor_view<address_space_enum::global>(
                 p_output,
                 make_tuple(num_rows_rem, kargs.topk),
                 make_tuple(kargs.stride_output, 1),
                 number<Problem::VectorSize>{},
                 number<1>{});
             auto view =
                 pad_tensor_view(tmp,
                                 make_tuple(number<Problem::RowsPerBlock>{}, number<1>{}),
                                 sequence<0, 0>{}); // 1. out-most dim no need pad(leverage oob)
                                                    // 2. we loop over topk 1-1, no need padding
             return make_tile_window(
                 view, make_tuple(number<Problem::RowsPerBlock>{}, number<1>{}), {0, 0});
         }();
  
         auto indices_window = [&]() {
             IndexType* p_indices = reinterpret_cast<IndexType*>(kargs.p_indices) + block_os_out;
             auto tmp             = make_naive_tensor_view<address_space_enum::global>(
                 p_indices,
                 make_tuple(num_rows_rem, kargs.topk),
                 make_tuple(kargs.stride_output, 1),
                 number<Problem::VectorSize>{},
                 number<1>{});
             auto view =
                 pad_tensor_view(tmp,
                                 make_tuple(number<Problem::RowsPerBlock>{}, number<1>{}),
                                 sequence<0, 0>{}); // 1. out-most dim no need pad(leverage oob)
                                                    // 2. we loop over topk 1-1, no need padding
             return make_tile_window(
                 view, make_tuple(number<Problem::RowsPerBlock>{}, number<1>{}), {0, 0});
         }();
  
         Pipeline{}(input_window,
                    output_window,
                    indices_window,
                    kargs.num_rows,
                    kargs.num_experts,
                    kargs.topk,
                    block_row_id);
     }
 };
 } // namespace ck_tile