Pad Tiling

Function Usage

Obtains the Pad tiling parameter.

Prototype

void GetPadMaxMinTmpSize(const ge::Shape &srcShape, const uint32_t typeSize, uint32_t &maxValue, uint32_t &minValue)

void PadTilingFunc(const ge::Shape srcShape, const ge::Shape oriSrcShape, const uint32_t stackBufferSize, const uint32_t typeSize, optiling::PadTiling& tiling)

Parameters

**Table 1** **GetPadMaxMinTmpSize** API parameters
Parameter	Input/Output	Meaning
srcShape	Input	Shape of the input tensor, which is two-dimensional.
typeSize	Input	Data type size of operator inputs. The unit is byte. For example, if the data type of operator inputs is half, set this parameter to 2.
maxValue	Output	Maximum size of the temporary space required by Pad computation. Maximum size of the temporary space required by Pad computation. Any space exceeding this value will not be utilized by the API. Within the range between the minimum and maximum, as the temporary space increases, the API computing performance in the kernel can be optimized to some extent. To achieve better performance, reserve or allocate the space based on the actual buffer usage. NOTE: maxValue is for reference only and may be larger than the available space of the Unified Buffer. In this case, select a proper temporary space size based on the remaining space of the Unified Buffer.
minValue	Output	Minimum size of the temporary space required by Pad computation. Minimum size of the temporary space required by Pad computation. To ensure correct functions, the size of the temporary space to be reserved or allocated during API computation cannot be less than the value of this parameter.

**Table 2** **PadTilingFunc** API parameters
Parameter	Input/Output	Meaning
srcShape	Input	Shape of the input tensor, which is two-dimensional (valid data + redundant data).
oriSrcShape	Input	Original shape of the input tensor, which is two-dimensional (valid data).
stackBufferSize	Input	Size of the space that can be used for Pad computation.
typeSize	Input	Data type size of operator inputs. The unit is byte. For example, if the data type of operator inputs is half, set this parameter to 2.
tiling	Output	Tiling information required by the Pad API.

Returns

None

Examples

The following example describes the process of obtaining the tiling parameter on the host and the method of using the parameter in the kernel when Pad high-level APIs are used. In the example, the shape of the input tensor and the original shape are both [320, 63], and the input data type is half.

Add the PadTiling structure parameter to the TilingData structure to function as a field.

BEGIN_TILING_DATA_DEF(TilingData)               // Register a tiling class and uses the tiling name as the input parameter.
  TILING_DATA_FIELD_DEF(uint32_t, totalLength); // Add the tiling field to compute the total data volume.
  TILING_DATA_FIELD_DEF(uint32_t, tileNum);     // Add the tiling field that specifies the total number of data blocks to be computed on each core.
  ...                                           // Add other tiling fields.
  TILING_DATA_FIELD_DEF_STRUCT(PadTiling, padTilingData); // Add the PadTiling structure parameter to the TilingData structure.
END_TILING_DATA_DEF;

The tiling implementation function first calls the GetPadMaxMinTmpSize API to obtain the maximum and minimum temporary space sizes required by the Pad API to complete computation, sets an appropriate space size based on this range and the actual buffer usage, and then obtains the tiling parameter required by the Pad kernel API based on the input shape and remaining size of computing space.

namespace optiling {
const uint32_t BLOCK_DIM = 8;
const uint32_t TILE_NUM = 8;
static ge::graphStatus TilingFunc(gert::TilingContext* context)
{
    TilingData tiling;
    uint32_t totalLength = context->GetInputTensor(0)->GetShapeSize();
    context->SetBlockDim(BLOCK_DIM);
    tiling.set_totalLength(totalLength);
    tiling.set_tileNum(TILE_NUM);
    // Set other tiling parameters.
    ...
    std::vector<int64_t> shapeVec = {320,63};
    ge::Shape srcShape(shapeVec);
    std::vector<int64_t> oriShapeVec = {320,63};
    ge::Shape oriSrcShape(oriShapeVec);

    uint32_t maxValue = 0;
    uint32_t minValue = 0;
    AscendC::GetPadMaxMinTmpSize(srcShape, sizeof(half), maxValue, minValue);
    // This example is for reference only. Obtain the minimum value and pass it to ensure correct functionality. Developers can pass a proper space size as required.
    const uint32_t localWorkSpaceSize = minValue;
    AscendC::PadTilingFunc(srcShape, oriSrcShape, localWorkSpaceSize , sizeof(half), tiling.padTilingData)
     ... // Other logic
    ...
    tiling.SaveToBuffer(context->GetRawTilingData()->GetData(), context->GetRawTilingData()->GetCapacity());
    context->GetRawTilingData()->SetDataSize(tiling.GetDataSize());
    context->SetTilingKey(1);
    return ge::GRAPH_SUCCESS;
}
} // namespace optiling

The kernel calls GET_TILING_DATA in the kernel function to obtain TilingData, and then passes the Pad Tiling information in TilingData to the Pad API for computation. For details about the complete example in the kernel, see Examples.

extern "C" __global__ __aicore__ void func_custom(GM_ADDR x, GM_ADDR y, GM_ADDR z, GM_ADDR workspace, GM_ADDR tiling)
{
    GET_TILING_DATA(tilingData, tiling);
    KernelFunc op;
    op.Init(x, y, z, tilingData.totalLength, tilingData.tileNum,tilingData.padTilingData);
    if (TILING_KEY_IS(1)) {
        op.Process();
    }
}

Parent topic: Data Padding