TPRINT

Tile Operation Diagram

TPRINT tile operation

Introduction

Print the contents of a Tile or GlobalTensor for debugging purposes directly from device code.

The TPRINT instruction outputs the logical view of data stored in a Tile or GlobalTensor. It supports common data types (e.g., float, half, int8, uint32) and multiple memory layouts (ND, DN, NZ for GlobalTensor; vector tiles for on-chip buffers).

Important: - This instruction is for development and debugging ONLY. - It incurs significant runtime overhead and must not be used in production kernels. - Output may be truncated if it exceeds the internal print buffer. The print buffer can be modified by adding -DCCEBlockMaxSize=16384 in compile options; default is 16KB. - Requires CCE compilation option -D_DEBUG --cce-enable-print (see Behavior).

Assembly Syntax

PTO-AS form: see PTO-AS Specification.

tprint %src : !pto.tile<...> | !pto.global<...>

AS Level 1 (SSA)

pto.tprint %src : !pto.tile<...> | !pto.partition_tensor_view<MxNxdtype> -> ()

AS Level 2 (DPS)

pto.tprint ins(%src : !pto.tile_buf<...> | !pto.partition_tensor_view<MxNxdtype>)

C++ Intrinsic

Declared in include/pto/common/pto_instr.hpp:

// For printing GlobalTensor or Vec-type Tile
template <PrintFormat Format = PrintFormat::Width8_Precision4, typename TileData>
PTO_INST void TPRINT(TileData &src);

// For printing Acc-type Tile and Mat-type Tile (Mat printing only supported for A3, not yet for A5)
template <PrintFormat Format = PrintFormat::Width8_Precision4, typename TileData, typename GlobalData>
PTO_INTERNAL void TPRINT(TileData &src, GlobalData &tmp);

PrintFormat Enumeration

Declared in include/pto/common/type.hpp:

enum class PrintFormat : uint8_t
{
    Width8_Precision4 = 0,  // Print width 8, precision 4
    Width8_Precision2 = 1,  // Print width 8, precision 2
    Width10_Precision6 = 2, // Print width 10, precision 6
};

Supported Types for T

  • Tile: TileType must be Vec, Acc, Mat (A3 only), and have a supported element type.
  • GlobalTensor: Must use layout ND, DN, or NZ, and have a supported element type.

Constraints

  • Supported element type:
    • Floating-point: float, half
    • Signed integers: int8_t, int16_t, int32_t
    • Unsigned integers: uint8_t, uint16_t, uint32_t
  • For GlobalTensor: Layout must be one of Layout::ND, Layout::DN, or Layout::NZ.
  • For temporary space: Printing a Tile with TileType of Mat or Acc requires temporary space on GM. The temporary space must not be less than TileData::Numel * sizeof(T).
  • A5 does not yet support printing Tiles with TileType of Mat.
  • Echo information: When TileType is Mat, the layout will be printed according to Layout::ND; other layouts may result in misaligned information.

Behavior

  • Mandatory Compilation Flag:

On A2/A3/A5 devices, TPRINT uses cce::printf to emit output via the device-to-host debug channel. You must enable the CCE option -D_DEBUG --cce-enable-print.

  • Buffer Limitation:

The internal print buffer of cce::printf is limited in size. If the output exceeds this buffer, a warning message such as "Warning: out of bound! try best to print" may appear, and only partial data will be printed.

  • Synchronization:

Automatically inserts a pipe_barrier(PIPE_ALL) before printing to ensure all prior operations complete and data is consistent.

  • Formatting:

    • Floating-point values: printed format depends on PrintFormat template parameter:
    • PrintFormat::Width8_Precision4: %8.4f (default)
    • PrintFormat::Width8_Precision2: %8.2f
    • PrintFormat::Width10_Precision6: %10.6f
    • Integer values: printed format depends on PrintFormat template parameter:
    • PrintFormat::Width8_Precision4 or PrintFormat::Width8_Precision2: %8d
    • PrintFormat::Width10_Precision6: %10d
    • For GlobalTensor, due to data size and buffer limitations, only elements within its logical shape (defined by Shape) are printed.
    • For Tile, invalid regions (beyond validRows/validCols) are still printed but marked with a | separator when partial validity is specified.

Examples

#include <pto/pto-inst.hpp>

PTO_INTERNAL void DebugTile(__gm__ float *src) {
  using ValidSrcShape = TileShape2D<float, 16, 16>;
  using NDSrcShape = BaseShape2D<float, 32, 32>;
  using GlobalDataSrc = GlobalTensor<float, ValidSrcShape, NDSrcShape>;
  GlobalDataSrc srcGlobal(src);

  using srcTileData = Tile<TileType::Vec, float, 16, 16>;
  srcTileData srcTile;
  TASSIGN(srcTile, 0x0);

  TLOAD(srcTile, srcGlobal);
  TPRINT(srcTile);
}

#include <pto/pto-inst.hpp>

PTO_INTERNAL void DebugGlobalTensor(__gm__ float *src) {
  using ValidSrcShape = TileShape2D<float, 16, 16>;
  using NDSrcShape = BaseShape2D<float, 32, 32>;
  using GlobalDataSrc = GlobalTensor<float, ValidSrcShape, NDSrcShape>;
  GlobalDataSrc srcGlobal(src);

  TPRINT(srcGlobal);
}

Math Interpretation

Unless otherwise specified, semantics are defined over the valid region and target-dependent behavior is marked as implementation-defined.

ASM Form Examples

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
pto.tprint %src : !pto.tile<...> | !pto.partition_tensor_view<MxNxdtype> -> ()

Manual Mode

# Manual mode: resources must be bound explicitly before issuing the instruction.
# Optional for tile operands:
# pto.tassign %arg0, @tile(0x1000)
# pto.tassign %arg1, @tile(0x2000)
pto.tprint %src : !pto.tile<...> | !pto.partition_tensor_view<MxNxdtype> -> ()

PTO Assembly Form

pto.tprint %src : !pto.tile<...> | !pto.partition_tensor_view<MxNxdtype> -> ()
# AS Level 2 (DPS)
pto.tprint ins(%src : !pto.tile_buf<...> | !pto.partition_tensor_view<MxNxdtype>)