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#include <miopen/pooling/solvers.hpp>

#include <miopen/pooling/invoke_params.hpp>
#include <miopen/datatype.hpp>
#include <miopen/pooling.hpp>
#include <miopen/kernel_build_params.hpp>
#include <miopen/target_properties.hpp>

namespace miopen {

namespace solver {

namespace pooling {

namespace {

struct kernel_params
{
    int kernel_size_h;
    int kernel_size_w;
    int kernel_stride_h;
    int kernel_stride_w;
    int out_pix_tile0;
    int out_pix_tile1;
    std::size_t batch_sz;
    std::size_t n_inputs;
    std::size_t in_height;
    std::size_t in_width;
    std::size_t grp_tile0;
    std::size_t grp_tile1;

    kernel_params(const miopen::pooling::ProblemDescription& problem)
    {
        const auto& pd = problem.GetPooling();

        kernel_size_w   = pd.lens[1];
        kernel_size_h   = pd.lens[0];
        kernel_stride_w = pd.strides[1];
        kernel_stride_h = pd.strides[0];

        std::tie(batch_sz, n_inputs, in_height, in_width) =
            miopen::tien<4>(problem.GetXDesc().GetLengths(), 1);

        out_pix_tile0 = 1;
        out_pix_tile1 = 1;
        if(pd.GetMode() == miopenPoolingMax)
        {
            out_pix_tile0 = in_width > 8 && in_width <= 24 ? 4 : 1;
            out_pix_tile1 = in_width <= 24 ? 1 : (in_width > 64 && in_width <= 96 ? 4 : 8);
        }

        grp_tile0 = 8;
        grp_tile1 = 8;
        if(pd.GetMode() == miopenPoolingMax)
        {
            grp_tile0 = in_width <= 8     ? 8  //
                        : in_width <= 16  ? 4  //
                        : in_width <= 24  ? 8  //
                        : in_width <= 32  ? 32 //
                        : in_width <= 64  ? 8  //
                        : in_width <= 96  ? 16 //
                        : in_width <= 128 ? 16
                                          : 32;
            grp_tile1 = in_width <= 8     ? 8  //
                        : in_width <= 16  ? 16 //
                        : in_width <= 24  ? 8  //
                        : in_width <= 32  ? 4  //
                        : in_width <= 64  ? 8  //
                        : in_width <= 96  ? 4  //
                        : in_width <= 128 ? 16
                                          : 4;
        }
    }
};

std::size_t sizeof_kernel_FLOAT(const miopen::pooling::ProblemDescription& problem)
{
    const auto datatype = problem.GetXDesc().GetType();
    return get_data_size(datatype);
}

std::size_t sizeof_kernel_index_t(const miopen::pooling::ProblemDescription& problem)
{
    return get_data_size(problem.GetPooling().GetIndexType());
}

inline std::size_t RoundUpToMultiple(std::size_t v, std::size_t m)
{
    assert(m > 0);
    return ((v + m - 1) / m) * m;
}

// Compute amount of local memory required for holding the arrays defined
// in the "mloPoolingAveBwd" and "mloPoolingMaxBwd" kernels.
std::size_t sizeof_local_memory(const miopen::pooling::ProblemDescription& problem)
{
    const kernel_params kp(problem);

    // aliases to ease programming
    const auto& MLO_POOLING_KERNEL_SZ0      = kp.kernel_size_w;
    const auto& MLO_POOLING_KERNEL_SZ1      = kp.kernel_size_h;
    const auto& MLO_POOLBWD_N_HORIZ_OUT_PIX = kp.out_pix_tile0;
    const auto& MLO_POOLBWD_N_VERT_OUT_PIX  = kp.out_pix_tile1;
    const auto& MLO_POOLING_STRIDE0         = kp.kernel_stride_w;
    const auto& MLO_POOLING_STRIDE1         = kp.kernel_stride_h;
    const auto& MLO_POOLBWD_GROUP_SZ0       = kp.grp_tile0;
    const auto& MLO_POOLBWD_GROUP_SZ1       = kp.grp_tile1;

    const auto MLO_POOLBWD_LCL_DATA_WIDTH =
        (static_cast<std::size_t>(MLO_POOLBWD_GROUP_SZ0) * MLO_POOLBWD_N_HORIZ_OUT_PIX +
         MLO_POOLING_KERNEL_SZ0 + MLO_POOLING_STRIDE0 - 2) /
        MLO_POOLING_STRIDE0;
    const auto MLO_POOLBWD_LCL_DATA_HEIGHT =
        (static_cast<std::size_t>(MLO_POOLBWD_GROUP_SZ1) * MLO_POOLBWD_N_VERT_OUT_PIX +
         MLO_POOLING_KERNEL_SZ1 + MLO_POOLING_STRIDE1 - 2) /
        MLO_POOLING_STRIDE1;

    std::size_t rv   = 0;
    const auto nelem = MLO_POOLBWD_LCL_DATA_WIDTH * MLO_POOLBWD_LCL_DATA_HEIGHT;
    if(problem.GetPooling().GetMode() == miopenPoolingMax)
    {
        const auto sizeof_lcl_top_df = sizeof_kernel_FLOAT(problem) * nelem;
        const auto sizeof_lcl_mask   = sizeof_kernel_index_t(problem) * nelem;
        /// \anchor alignment_of_arrays_in_gpu_memory
        /// The total amount of memory calculated here is slightly less than the amount calculated
        /// by the compiler. As a result, the check here may pass, while then the compiler might
        /// refuse to build the kernel. The most likely reason for the difference is padding (due to
        /// alignment requirements). We don't know exactly how the compiler takes alignment into
        /// account, but what can we do is applying an alignment that imposes a slightly tighter
        /// constraints than the compiler. So far, 16-byte (4xDWORD) alignment works well.
        rv = RoundUpToMultiple(sizeof_lcl_top_df, 16) + RoundUpToMultiple(sizeof_lcl_mask, 16);
    }
    else
    {
        const auto sizeof_lcl_top_diff = sizeof_kernel_FLOAT(problem) * nelem;
        rv                             = RoundUpToMultiple(sizeof_lcl_top_diff, 16);
    }
    MIOPEN_LOG_T(rv);
    return rv;
}

} // namespace

bool PoolingBackward2d::IsApplicable(const ExecutionContext&,
                                     const miopen::pooling::ProblemDescription& problem) const
{
    return problem.GetDirection() == miopen::pooling::Direction::Backward &&
           (problem.GetPooling().GetMode() == miopenPoolingMax ||
            problem.GetPooling().GetMode() == miopenPoolingAverage ||
            problem.GetPooling().GetMode() == miopenPoolingAverageInclusive) &&
           problem.GetXDesc().GetSize() == 4 && problem.GetXDesc().GetLayout("NCHW") == "NCHW" &&
           problem.GetYDesc().GetLayout("NCHW") == "NCHW" &&
           sizeof_local_memory(problem) <= TargetProperties::GetMaxLocalMemorySize();
}

ConvSolution
PoolingBackward2d::GetSolution(const ExecutionContext&,
                               const miopen::pooling::ProblemDescription& problem) const
{
    auto result = ConvSolution{miopenStatusSuccess};

    const kernel_params kp(problem);

    {
        auto kernel = KernelInfo{};

        kernel.kernel_file = "MIOpenPoolingBwd.cl";

        if(problem.GetPooling().GetMode() == miopenPoolingMax)
        {
            kernel.kernel_name = "mloPoolingMaxBwd";
        }
        else if(problem.GetPooling().GetMode() == miopenPoolingAverage ||
                problem.GetPooling().GetMode() == miopenPoolingAverageInclusive)
        {
            kernel.kernel_name = "mloPoolingAveBwd";
        }

        const int pooling_method = (problem.GetPooling().GetMode() == miopenPoolingMax)
                                       ? MLO_POOLING_OP_MAX
                                       : ((problem.GetPooling().GetMode() == miopenPoolingAverage)
                                              ? MLO_POOLING_OP_AVE
                                              : MLO_POOLING_OP_AVE_INCLUSIVE);

        const int g_wk_width  = ((kp.in_width + kp.grp_tile0 * kp.out_pix_tile0 - 1) /
                                (kp.grp_tile0 * kp.out_pix_tile0));
        const int g_wk_height = ((kp.in_height + kp.grp_tile1 * kp.out_pix_tile1 - 1) /
                                 (kp.grp_tile1 * kp.out_pix_tile1));

        const auto build_params =
            KernelBuildParameters{
                {"MLO_POOLING_OP_ID", pooling_method},
                {"MLO_POOLING_KERNEL_SZ1", kp.kernel_size_h},
                {"MLO_POOLING_STRIDE1", kp.kernel_stride_h},
                {"MLO_POOLING_KERNEL_SZ0", kp.kernel_size_w},
                {"MLO_POOLING_STRIDE0", kp.kernel_stride_w},
                {"MLO_POOLBWD_N_HORIZ_OUT_PIX", kp.out_pix_tile0},
                {"MLO_POOLBWD_N_VERT_OUT_PIX", kp.out_pix_tile1},
                {"MLO_POOLBWD_GROUP_SZ0", kp.grp_tile0},
                {"MLO_POOLBWD_GROUP_SZ1", kp.grp_tile1},
                {"MLO_POOLING_INDEX_TYPE",
                 get_pooling_index_type_name(problem.GetPooling().GetIndexType())},
                {"MLO_POOLING_INDEX_MAX",
                 get_pooling_index_type_max_name(problem.GetPooling().GetIndexType())},
                {"USE_IMG_INDEX",
                 problem.GetPooling().GetWorkspaceIndexMode() == miopenPoolingWorkspaceIndexImage
                     ? 1
                     : 0},
            }
            << GetDataTypeKBP(problem.GetXDesc().GetType());

        kernel.comp_options = build_params.GenerateFor(kbp::OpenCL{});

        kernel.l_wk = {kp.grp_tile0, kp.grp_tile1, 1};
        kernel.g_wk = {
            g_wk_width * kp.grp_tile0, g_wk_height * kp.grp_tile1, kp.n_inputs * kp.batch_sz};

        result.construction_params.push_back(kernel);
    }

    result.invoker_factory = [](const std::vector<Kernel>& kernels) {
        return [=](const Handle& handle_, const AnyInvokeParams& raw_params) {
            decltype(auto) kernel = handle_.Run(kernels.front());
            decltype(auto) params = raw_params.CastTo<miopen::pooling::BwdInvokeParams>();

            if(params.pooling.GetMode() == miopenPoolingMax)
            {
                kernel(params.dy,
                       params.dx,
                       params.workspace,
                       static_cast<int>(params.pooling.pads[0]),
                       static_cast<int>(params.pooling.pads[1]),
                       static_cast<int>(params.dyDesc.GetLengths()[1]),
                       static_cast<int>(params.dxDesc.GetLengths()[2]),
                       static_cast<int>(params.dxDesc.GetLengths()[3]),
                       static_cast<int>(params.dyDesc.GetLengths()[2]),
                       static_cast<int>(params.dyDesc.GetLengths()[3]),
                       static_cast<int>(params.dxDesc.GetStrides()[0]),
                       static_cast<int>(params.dxDesc.GetStrides()[1]),
                       static_cast<int>(params.dxDesc.GetStrides()[2]),
                       static_cast<int>(params.dyDesc.GetStrides()[0]),
                       static_cast<int>(params.dyDesc.GetStrides()[1]),
                       static_cast<int>(params.dyDesc.GetStrides()[2]));
            }
            else
            {
                kernel(params.dy,
                       params.dx,
                       static_cast<int>(params.pooling.pads[0]),
                       static_cast<int>(params.pooling.pads[1]),
                       static_cast<int>(params.dyDesc.GetLengths()[1]),
                       static_cast<int>(params.dxDesc.GetLengths()[2]),
                       static_cast<int>(params.dxDesc.GetLengths()[3]),
                       static_cast<int>(params.dyDesc.GetLengths()[2]),
                       static_cast<int>(params.dyDesc.GetLengths()[3]),
                       static_cast<int>(params.dxDesc.GetStrides()[0]),
                       static_cast<int>(params.dxDesc.GetStrides()[1]),
                       static_cast<int>(params.dxDesc.GetStrides()[2]),
                       static_cast<int>(params.dyDesc.GetStrides()[0]),
                       static_cast<int>(params.dyDesc.GetStrides()[1]),
                       static_cast<int>(params.dyDesc.GetStrides()[2]));
            }
        };
    };

    return result;
}

std::size_t
PoolingBackward2d::GetWorkspaceSize(const ExecutionContext&,
                                    const miopen::pooling::ProblemDescription& problem) const
{
    if(problem.GetPooling().GetMode() != miopenPoolingMax)
        return 0;
    return problem.GetYDesc().GetElementSize() * get_data_size(problem.GetPooling().GetIndexType());
}

} // namespace pooling

} // namespace solver

} // namespace miopen
