FZGPUModules 2.0
GPU-accelerated modular compression pipelines
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fz::Stage Class Referenceabstract

#include <stage.h>

+ Inheritance diagram for fz::Stage:

Public Member Functions

virtual void execute (fz::stream_t stream, MemoryPool *pool, const std::vector< void * > &inputs, const std::vector< void * > &outputs, const std::vector< size_t > &sizes)=0
 
virtual std::string getName () const =0
 
virtual size_t getRequiredInputAlignment () const
 
virtual std::vector< std::string > getOutputNames () const
 
int getOutputIndex (const std::string &name) const
 
virtual std::vector< size_t > estimateOutputSizes (const std::vector< size_t > &input_sizes) const =0
 
virtual std::unordered_map< std::string, size_t > getActualOutputSizesByName () const =0
 
virtual size_t getActualOutputSize (int index) const
 
virtual void setInverse (bool inverse)
 
virtual uint16_t getStageTypeId () const =0
 
virtual uint8_t getOutputDataType (size_t output_index) const =0
 
virtual uint8_t getInputDataType (size_t) const
 
virtual size_t serializeHeader (size_t output_index, uint8_t *header_buffer, size_t max_size) const
 
virtual void deserializeHeader (const uint8_t *header_buffer, size_t size)
 
virtual void saveState ()
 
virtual std::vector< std::string > getRunNotes () const
 
virtual void setDims (const std::array< size_t, 3 > &dims)
 
virtual void onFinalize (size_t, MemoryPool *)
 
virtual size_t estimateDeviceFootprintBytes (size_t) const
 
virtual size_t estimatePinnedFootprintBytes (size_t) const
 
virtual void postStreamSync (fz::stream_t stream)
 
virtual size_t getMaxHeaderSize (size_t output_index) const
 
virtual bool isGraphCompatible () const
 
virtual size_t estimateScratchBytes (const std::vector< size_t > &input_sizes) const
 

Static Public Member Functions

static constexpr bool isSupportedOnBackend ()
 

Detailed Description

Base class for all compression/decompression stages.

A stage is a single transformation in the pipeline (e.g. Lorenzo predictor, RLE encoder, bitshuffle). The pipeline interacts with stages exclusively through this interface — no downcasting or type-name branching anywhere in the pipeline or DAG code.

Member Function Documentation

◆ isSupportedOnBackend()

static constexpr bool fz::Stage::isSupportedOnBackend ( )
inlinestaticconstexpr

Whether this stage type is supported on the backend the library was built for. Default true (every stage supports every backend) — a stage that doesn't (e.g. ANSStage on HIP/SYCL, whose vendored PTX lanemask assembly has no translation) hides this with its own static constexpr bool isSupportedOnBackend().

Deliberately static constexpr, not virtual: Pipeline::addStage<T>() must be able to check this before T is ever constructed, via if constexpr, so that on an unsupported backend the new T() branch is never instantiated at all — not merely never executed. That matters because an unsupported stage's own translation unit may be excluded from the build entirely (see CMakeLists.txt's HEADER_FILE_ONLY handling for ans_stage.cu on HIP); a virtual/instance method can't be called without an object to call it on, which would require the very constructor this mechanism exists to avoid referencing.

◆ execute()

virtual void fz::Stage::execute ( fz::stream_t  stream,
MemoryPool pool,
const std::vector< void * > &  inputs,
const std::vector< void * > &  outputs,
const std::vector< size_t > &  sizes 
)
pure virtual

Execute the stage. Inputs, outputs, and sizes are device pointers/bytes.

Stages may call cudaStreamSynchronize(stream) or issue blocking D2H copies when the algorithm requires it (e.g. Huffman histogram readback for codebook construction, ANS renormalization tables). Such stages must return false from isGraphCompatible() and must document the sync points.

Note: the DAG dispatches sibling nodes (same topological level) via a sequential CPU loop, each enqueuing to its own stream. A sync inside execute() blocks the CPU from dispatching subsequent siblings until the synced stream is idle — this delays parallel branches in wide DAGs. In a linear pipeline there are no siblings and no extra cost.

Implemented in fz::CLOGStage, fz::HCLOGStage, fz::RAREStage, fz::RAZEStage, fz::LogTransformStage< TInput >, fz::AdaptiveBitpackStage< T >, fz::BitpackStage< T >, fz::GPULZStage, fz::HuffmanStage< T >, fz::RLEStage< T >, fz::RREStage, fz::RZEStage, fz::AdaptiveLorenzoStage< T >, fz::BitplaneRZEStage, fz::GInterpStage< TInput, TCode >, fz::LorenzoQuantStage< TInput, TCode >, fz::DifferenceStage< T, TOut, Mode >, fz::LorenzoStage< T >, fz::TiledLorenzoStage< T >, fz::QuantizerStage< TInput, TCode >, fz::BitshuffleStage, fz::TUPLStage, fz::MergeStage, fz::NegabinaryStage< TIn, TOut >, and fz::ZigzagStage< TIn, TOut >.

◆ getName()

◆ getRequiredInputAlignment()

virtual size_t fz::Stage::getRequiredInputAlignment ( ) const
inlinevirtual

Minimum input size alignment in bytes. Chunked stages return their chunk size; the pipeline uses the LCM of all stage alignments at finalize() to transparently zero-pad the input. Default: 1 (no alignment requirement).

Reimplemented in fz::CLOGStage, fz::GPULZStage, fz::HCLOGStage, fz::RAREStage, fz::RAZEStage, fz::RLEStage< T >, fz::RREStage, fz::RZEStage, fz::DifferenceStage< T, TOut, Mode >, fz::BitshuffleStage, and fz::TUPLStage.

◆ getOutputNames()

virtual std::vector< std::string > fz::Stage::getOutputNames ( ) const
inlinevirtual

Output port names in order. Default: single port named "output". Multi-output stages (e.g. Lorenzo: "codes", "outliers") override this.

Reimplemented in fz::GPULZStage, fz::AdaptiveLorenzoStage< T >, fz::GInterpStage< TInput, TCode >, fz::LorenzoQuantStage< TInput, TCode >, fz::LorenzoStage< T >, fz::QuantizerStage< TInput, TCode >, fz::MergeStage, and fz::LogTransformStage< TInput >.

◆ getOutputIndex()

int fz::Stage::getOutputIndex ( const std::string &  name) const
inline

Returns the index of a named output port, or -1 if not found.

◆ estimateOutputSizes()

virtual std::vector< size_t > fz::Stage::estimateOutputSizes ( const std::vector< size_t > &  input_sizes) const
pure virtual

◆ getActualOutputSizesByName()

◆ getActualOutputSize()

◆ setInverse()

◆ getStageTypeId()

◆ getOutputDataType()

◆ getInputDataType()

virtual uint8_t fz::Stage::getInputDataType ( size_t  ) const
inlinevirtual

Expected DataType of the given input port.

Used by Pipeline::finalize() to detect type mismatches between connected stages before any execution. Return DataType::UNKNOWN to opt out of checking — byte-transparent stages (Bitshuffle, RZE, RRE) and mock stages must return UNKNOWN; finalize() skips any connection where either side is UNKNOWN.

Reimplemented in fz::AdaptiveLorenzoStage< T >, fz::LogTransformStage< TInput >, fz::AdaptiveBitpackStage< T >, fz::BitpackStage< T >, fz::GPULZStage, fz::HuffmanStage< T >, fz::RLEStage< T >, fz::BitplaneRZEStage, fz::GInterpStage< TInput, TCode >, fz::LorenzoQuantStage< TInput, TCode >, fz::DifferenceStage< T, TOut, Mode >, fz::LorenzoStage< T >, fz::TiledLorenzoStage< T >, fz::QuantizerStage< TInput, TCode >, fz::MergeStage, fz::NegabinaryStage< TIn, TOut >, and fz::ZigzagStage< TIn, TOut >.

◆ serializeHeader()

◆ deserializeHeader()

◆ saveState()

virtual void fz::Stage::saveState ( )
inlinevirtual

◆ getRunNotes()

virtual std::vector< std::string > fz::Stage::getRunNotes ( ) const
inlinevirtual

Notes about what this stage actually did on the last run, when that differs from what was configured in a way that affects comparability.

Motivating case: HuffmanStage silently falls back to an Adaptive book when a PerBlock/Fixed build drives a symbol past the 27-bit code field. The fallback is correct — it does not relax the error bound — but a field encoded with a different codebook is not compression-ratio comparable to one that was not, and getBookSource() deliberately keeps reporting what was asked for. Without a channel like this, a benchmark row records the two cases identically and the difference is unrecoverable after the fact.

Returns short stable machine-readable tokens (e.g. "adaptive_fallback"), not prose — these are meant to land in a benchmark row and be grouped on. Empty by default; a stage that never surprises its caller need not implement it.

Reimplemented in fz::HuffmanStage< T >.

◆ setDims()

virtual void fz::Stage::setDims ( const std::array< size_t, 3 > &  dims)
inlinevirtual

Called once by Pipeline::finalize() so stages can react to the dataset dimensions set via Pipeline::setDims() after construction.

Parameters
dims{x, y, z} extents (z==1 → 2-D; y==z==1 → 1-D)

Reimplemented in fz::GInterpStage< TInput, TCode >, fz::LorenzoQuantStage< TInput, TCode >, fz::LorenzoStage< T >, fz::TiledLorenzoStage< T >, and fz::QuantizerStage< TInput, TCode >.

◆ onFinalize()

virtual void fz::Stage::onFinalize ( size_t  ,
MemoryPool  
)
inlinevirtual

Called once by Pipeline::finalize() after buffer-size propagation, with this stage's estimated input size (bytes) and the pipeline pool.

Implement this to pre-allocate persistent stage-internal scratch (e.g. Huffman codebook/histogram buffers) via pool->allocatePersistentDevice and pool->allocatePersistentPinned rather than via cudaMalloc directly. Pre-allocating here makes PREALLOCATE mode semantically correct (all memory committed at finalize time) and makes the stage footprint visible via pool->getPersistentDeviceBytes() / getPersistentPinnedBytes().

Stages that also allow lazy allocation (e.g. for capacity-growth realloc in execute()) should check whether pool was already used to allocate here and skip the lazy path if so.

Default: no-op.

Reimplemented in fz::HuffmanStage< T >, fz::GInterpStage< TInput, TCode >, fz::LorenzoQuantStage< TInput, TCode >, fz::QuantizerStage< TInput, TCode >, and fz::LogTransformStage< TInput >.

◆ estimateDeviceFootprintBytes()

virtual size_t fz::Stage::estimateDeviceFootprintBytes ( size_t  ) const
inlinevirtual

Estimated persistent device memory this stage allocates outside the pool (via pool->allocatePersistentDevice). Used for total footprint reporting. Default: 0.

Reimplemented in fz::HuffmanStage< T >, fz::GInterpStage< TInput, TCode >, fz::LorenzoQuantStage< TInput, TCode >, fz::QuantizerStage< TInput, TCode >, and fz::LogTransformStage< TInput >.

◆ estimatePinnedFootprintBytes()

virtual size_t fz::Stage::estimatePinnedFootprintBytes ( size_t  ) const
inlinevirtual

Estimated persistent pinned-host memory this stage allocates outside the pool (via pool->allocatePersistentPinned). Used for total footprint reporting. Default: 0.

Reimplemented in fz::HuffmanStage< T >, and fz::GInterpStage< TInput, TCode >.

◆ postStreamSync()

virtual void fz::Stage::postStreamSync ( fz::stream_t  stream)
inlinevirtual

Called after dag->execute() and stream sync, before compress() returns. Use for D2H transfers that must not block mid-pipeline (e.g. Lorenzo's outlier count readback). The stream is already idle so a plain cudaMemcpy is safe here.

Reimplemented in fz::CLOGStage, fz::HCLOGStage, fz::RAREStage, fz::RAZEStage, fz::AdaptiveBitpackStage< T >, fz::GPULZStage, fz::RLEStage< T >, fz::RREStage, fz::RZEStage, fz::AdaptiveLorenzoStage< T >, fz::GInterpStage< TInput, TCode >, fz::LorenzoQuantStage< TInput, TCode >, fz::QuantizerStage< TInput, TCode >, and fz::LogTransformStage< TInput >.

◆ getMaxHeaderSize()

◆ isGraphCompatible()

virtual bool fz::Stage::isGraphCompatible ( ) const
inlinevirtual

Whether this stage is safe inside a CUDA Graph capture.

A stage is graph-compatible if execute() enqueues only device-side work (kernel launches, cudaMemcpyAsync D2D/H2D) and makes no host-synchronous calls. Override and return false if execute() contains D2H copies or dynamic decisions based on device data — the DAG will throw at setCaptureMode(true) time rather than producing a broken graph.

Default: true. Inverse-mode stages that do D2H reads (e.g. RZE inverse) must return false.

Reimplemented in fz::AdaptiveBitpackStage< T >, fz::BitpackStage< T >, fz::CLOGStage, fz::GPULZStage, fz::HCLOGStage, fz::HuffmanStage< T >, fz::RAREStage, fz::RAZEStage, fz::RREStage, fz::RZEStage, fz::AdaptiveLorenzoStage< T >, fz::BitplaneRZEStage, fz::GInterpStage< TInput, TCode >, fz::MergeStage, and fz::LogTransformStage< TInput >.

◆ estimateScratchBytes()

virtual size_t fz::Stage::estimateScratchBytes ( const std::vector< size_t > &  input_sizes) const
inlinevirtual

Peak persistent scratch bytes this stage holds in the MemoryPool.

Only count allocations that are drawn from the pool and kept alive across execute() calls. Transient scratch freed within execute() is already captured by the pool's high-water mark and must not be included. Used by CompressionDAG::computeTopoPoolSize() to size the release threshold.

Reimplemented in fz::AdaptiveBitpackStage< T >, fz::CLOGStage, fz::GPULZStage, fz::HCLOGStage, fz::RAREStage, fz::RAZEStage, fz::RLEStage< T >, fz::RREStage, fz::RZEStage, and fz::AdaptiveLorenzoStage< T >.