Files
cutlass/include/cutlass/subbyte_reference.h
Vijay Thakkar be60a0b272 CUTLASS 3.5.1 (#1623)
* CUTLASS 3.5.1

* updates, optimizations, fixes
2024-07-29 08:46:24 -04:00

1391 lines
40 KiB
C++

/***************************************************************************************************
* Copyright (c) 2017 - 2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*
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*
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* list of conditions and the following disclaimer.
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/*! \file
\brief Provides a mechanism for packing and unpacking elements smaller than one byte
*/
#pragma once
#include "cutlass/cutlass.h"
#include "cutlass/integer_subbyte.h"
#include "cutlass/fast_math.h"
namespace cutlass {
namespace detail {
// This is an implementation detail of cutlass::SubbyteReference and.
// cutlass::HostTensor. For a given logical element type Element,
// and its corresponding storage (physical) element type StorageUnit,
// it computes quantities that help with managing allocations.
//
// CUTLASS uses a hidden "ContainerUnitType" or StorageUnit type to support
// packed arrays of subbyte types such as int4. Element is the "logical" type
// for computations, while CUTLASS uses StorageUnit as the element type
// of a packed array of Element. If Element is not a subbyte type,
// then the corresponding StorageUnit type is just Element itself.
//
// The ContainerType is always calculated as an array StorageUnit type (the StorageUnit
// is always a byte for subbyte types),
// and its number of bits is the lcm of the subbyte type's number of bits and 8.
// Below are some examples for different subbyte types.
//
// * Subbyte Type=int2, ContainerType=StorageUnit[1] (StorageUnit=uint8_t)
// * Subbyte Type=int4, ContainerType=StorageUnit[1] (StorageUnit=uint8_t)
template<class Element, class StorageUnit>
struct StorageContainerCalculator {
// kContainerTypeNumBits: The number of bits needed for ContainerType
static constexpr int kContainerTypeNumBits = (sizeof_bits<Element>::value < 8) ? cutlass::lcm_cxx11(sizeof_bits<Element>::value, sizeof_bits<StorageUnit>::value) : sizeof_bits<Element>::value;
static_assert(kContainerTypeNumBits % sizeof_bits<Element>::value == 0, "The bits of ContainerType should be divisible by the element's number of bits");
// kContainerTypeNumLogicalElements: The number of logical Element instance(s) that can be stored per ContainerType instance
static constexpr int kContainerTypeNumLogicalElements = kContainerTypeNumBits / sizeof_bits<Element>::value;
/// 3. kContainerTypeNumBytes: The number of bytes per ContainerType instance
static constexpr int kContainerTypeNumBytes = kContainerTypeNumBits / 8;
/// 4. kContainerTypeNumBytes: The number of base StorageUnit in the ContainerType
static constexpr int kContainerTypeNumStorageUnit = kContainerTypeNumBits / sizeof_bits<StorageUnit>::value;
static_assert(kContainerTypeNumBits != 0, "kContainerTypeNumBits can not be zero");
static_assert(kContainerTypeNumLogicalElements != 0, "kContainerTypeNumLogicalElements can not be zero");
static_assert(kContainerTypeNumBytes != 0, "kContainerTypeNumBytes can not be zero");
};
}
/////////////////////////////////////////////////////////////////////////////////////////////////
/// This class provides a mechanism for packing and unpacking elements smaller than one byte. It
/// assumes these sub-byte elements are packed in a traditional C++ numeric type.
///
/// The intended application is to provide a mechanism to indirectly reference elements in
/// memory or Array<> objects whose addresses cannot otherwise be taken since they are smaller
/// than one byte.
///
/// Supports basic pointer arithmetic:
///
/// Example:
///
/// int4b_t *ptr = ...;
///
/// SubbyteReference<int4b_t> ref = ptr;
/// ref += 15;
///
/// int4b_t x = ref; // load an int4b_t
/// ref = x + 2_s4; // perform arithmetic on int4b_t and then store
///
template <
typename Element_, /// CUTLASS numeric element type.
typename Storage_ = uint8_t, /// Underlying storage type. Must be able to hold an integer
/// number of objects of type Element.
class = void
>
class ConstSubbyteReference {
public:
using Element = Element_;
using Storage = Storage_;
using StoragePointer = Storage const *;
static_assert(sizeof_bits<Element>::value <= sizeof_bits<Storage>::value,
"Size of Element must not be greater than Storage.");
static_assert(!(sizeof_bits<Storage>::value % sizeof_bits<Element>::value),
"Storage must be divisible by Element");
private:
///! Number of elements per storage vector
int const kElementsPerVector = sizeof_bits<Storage>::value / sizeof_bits<Element>::value;
///! Bit mask
Storage const kMask =
((sizeof_bits<Element>::value < sizeof_bits<Storage>::value) ?
(Storage(1) << sizeof_bits<Element>::value) - Storage(1) :
~Storage(0));
private:
/// Pointer to array containing element
StoragePointer ptr_;
/// Offset (in units of elements) from pointer.
///
/// Invariant: must always be in range [0, kElementsPerVector)
int offset_;
public:
CUTLASS_HOST_DEVICE
ConstSubbyteReference(): ptr_(nullptr), offset_(0) { }
/// Constructor
CUTLASS_HOST_DEVICE
ConstSubbyteReference(
Element const *ptr, /// pointer to memory
int64_t offset /// logical offset in units of Element
):
ptr_(reinterpret_cast<StoragePointer>(ptr)),
offset_(0) {
int64_t offset_in_vectors = offset / kElementsPerVector;
int64_t offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = int(offset_in_elements);
}
/// Constructor
CUTLASS_HOST_DEVICE
ConstSubbyteReference(
Element *ptr = nullptr
): ConstSubbyteReference(ptr, 0) { }
/// Gets storage pointer
CUTLASS_HOST_DEVICE
StoragePointer storage_pointer() const {
return ptr_;
}
/// Gets element offset within storage vector
CUTLASS_HOST_DEVICE
int element_offset() const {
return offset_;
}
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
Element get() const {
Storage item = Storage((*ptr_ >> (offset_ * sizeof_bits<Element>::value)) & kMask);
return reinterpret_cast<Element const &>(item);
}
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
operator Element() const {
return get();
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator+=(int offset) {
offset += offset_;
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator+=(long long offset) {
offset += offset_;
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator-=(int offset) {
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator-=(long long offset) {
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
return *this;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator+(int offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator+(long long offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator-(int offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator-=(long long offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Computes the difference in elements between references
CUTLASS_HOST_DEVICE
ptrdiff_t operator-(ConstSubbyteReference ref) const {
return (ptr_ - ref.ptr_) * kElementsPerVector + (offset_ - ref.offset_);
}
/// Explicit cast to int
CUTLASS_HOST_DEVICE
explicit operator int() const {
return int(get());
}
/// Explicit cast to signed 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator int64_t() const {
return int64_t(get());
}
/// Explicit cast to unsigned 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator uint64_t() const {
return uint64_t(get());
}
/// Explicit cast to float
CUTLASS_HOST_DEVICE
explicit operator float() const {
return float(get());
}
/// Explicit cast to double
CUTLASS_HOST_DEVICE
explicit operator double() const {
return double(get());
}
};
template <
typename Element_, /// CUTLASS numeric element type.
typename Storage_ = /// Underlying storage type. Must be able to hold an integer
/// number of objects of type Element.
#if defined(__CUDA_ARCH__) /// Default size depends on width of atomicCas() overloads.
#if (__CUDA_ARCH__ >= 700) ///
uint16_t
#else
uint32_t
#endif
#else
uint8_t
#endif
,
class = void
>
class SubbyteReference {
public:
using Element = Element_;
using Storage = Storage_;
using StoragePointer = Storage *;
static_assert(sizeof_bits<Element>::value <= sizeof_bits<Storage>::value,
"Size of Element must not be greater than Storage.");
static_assert(!(sizeof_bits<Storage>::value % sizeof_bits<Element>::value),
"Storage must be divisible by Element");
private:
///! Number of elements per storage vector
int const kElementsPerVector = sizeof_bits<Storage>::value / sizeof_bits<Element>::value;
///! Bit mask
Storage const kMask =
((sizeof_bits<Element>::value < sizeof_bits<Storage>::value) ?
(Storage(1) << sizeof_bits<Element>::value) - Storage(1) :
~Storage(0));
private:
/// Pointer to array containing element
StoragePointer ptr_;
/// Offset (in units of elements) from pointer.
///
/// Invariant: must always be in range [0, kElementsPerVector)
int offset_;
public:
CUTLASS_HOST_DEVICE
SubbyteReference(): ptr_(nullptr), offset_(0) { }
/// Constructor
CUTLASS_HOST_DEVICE
SubbyteReference(
Element *ptr, /// pointer to memory
int64_t offset /// logical offset in units of Element
):
ptr_(reinterpret_cast<StoragePointer>(ptr)),
offset_(0) {
int64_t offset_in_vectors = offset / kElementsPerVector;
int64_t offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = int(offset_in_elements);
}
/// Constructor
CUTLASS_HOST_DEVICE
SubbyteReference(
Element *ptr = nullptr
): SubbyteReference(ptr, 0) { }
/// Gets storage pointer
CUTLASS_HOST_DEVICE
StoragePointer storage_pointer() const {
return ptr_;
}
/// Gets storage pointer
CUTLASS_HOST_DEVICE
Element * operator&() const {
return reinterpret_cast<Element *>(ptr_);
}
/// Gets element offset within storage vector
CUTLASS_HOST_DEVICE
int element_offset() const {
return offset_;
}
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
Element get() const {
uint8_t const* byte_ptr = reinterpret_cast<uint8_t const*>(ptr_);
// Convert offset in elements to offset in bytes
constexpr int elements_per_byte = cutlass::sizeof_bits<uint8_t>::value / cutlass::sizeof_bits<Element>::value;
byte_ptr += offset_ / elements_per_byte;
// Offset of element within a byte
int byte_offset = offset_ % elements_per_byte;
uint8_t item = uint8_t((*byte_ptr >> (byte_offset * cutlass::sizeof_bits<Element>::value)) & kMask);
return reinterpret_cast<Element const &>(item);
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference & set(Element const &x) {
Storage item = (reinterpret_cast<Storage const &>(x) & kMask);
Storage kUpdateMask = Storage(~(kMask << (offset_ * cutlass::sizeof_bits<Element>::value)));
Storage new_bits = Storage(item << (offset_ * cutlass::sizeof_bits<Element>::value));
#if defined(__CUDA_ARCH__)
//
// Homebrew read-modify-write
//
Storage original;
Storage updated;
do {
original = (*ptr_);
updated = Storage((original & kUpdateMask) | new_bits);
original = atomicCAS(ptr_, original, updated);
} while (updated != original);
#else
Storage original = (*ptr_);
Storage updated = Storage((original & kUpdateMask) | new_bits);
*ptr_ = updated;
#endif
return *this;
}
////
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
operator Element() const {
return get();
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference &operator=(Element const & x) {
return set(x);
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference &operator=(SubbyteReference const & x) {
return set(x.get());
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference &operator=(
ConstSubbyteReference<Element, Storage> const &x) {
return set(x.get());
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator+=(int offset) {
offset += offset_;
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator+=(long long offset) {
offset += offset_;
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator-=(int offset) {
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator-=(long long offset) {
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
return *this;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator+(int offset) const {
SubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator+(long long offset) const {
SubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator-(int offset) const {
SubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator-=(long long offset) const {
SubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Computes the difference in elements between references
CUTLASS_HOST_DEVICE
ptrdiff_t operator-(SubbyteReference ref) const {
return (ptr_ - ref.ptr_) * kElementsPerVector + (offset_ - ref.offset_);
}
/// Explicit cast to int
CUTLASS_HOST_DEVICE
explicit operator int() const {
return int(get());
}
/// Explicit cast to signed 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator int64_t() const {
return int64_t(get());
}
/// Explicit cast to unsigned 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator uint64_t() const {
return uint64_t(get());
}
/// Explicit cast to float
CUTLASS_HOST_DEVICE
explicit operator float() const {
return float(get());
}
/// Explicit cast to double
CUTLASS_HOST_DEVICE
explicit operator double() const {
return double(get());
}
};
/////////////////////////////////////////////////////////////////////////////////////////////////
template<typename T> using _war = T;
template <
typename Element_, /// CUTLASS numeric element type.
typename Storage_ /// Underlying basic storage type.
>
class SubbyteReference<Element_, Storage_,
typename platform::enable_if<sizeof_bits<Storage_>::value % sizeof_bits<Element_>::value != 0>::type> {
public:
using Element = Element_;
/// Note: It's possible that StorageUnit is not divisible by Element.
/// For example, an Element instance might be stored across 2 StorageUnit instances.
/// Thus, CUTLASS needs a storage vector to hold an integer number of Element instances.
using StorageUnit = Storage_;
private:
using StorageContainerCalculator = cutlass::detail::StorageContainerCalculator<Element, StorageUnit>;
public:
static int const kBitsStoredVec = StorageContainerCalculator::kContainerTypeNumBits;
static int const kNumStorageUnitPerStoredVec = StorageContainerCalculator::kContainerTypeNumStorageUnit;
using StorageVec = StorageUnit[kNumStorageUnitPerStoredVec];
using StorageVecPointer = StorageVec *;
using CudaAtomicType = typename platform::conditional<
sizeof_bits<StorageUnit>::value == 16,
uint32_t,
uint64_t
>::type;
static_assert(sizeof_bits<Element>::value <= sizeof_bits<StorageVec>::value,
"Size of Element must not be greater than StorageVec.");
static_assert(!(sizeof_bits<StorageVec>::value % sizeof_bits<Element>::value),
"StorageVec must be divisible by Element");
private:
///! Number of elements per storage vector
int const kElementsPerVector = sizeof_bits<StorageVec>::value / sizeof_bits<Element>::value;
///! Bit mask for storage unit.
StorageUnit const kMask = (StorageUnit(1) << sizeof_bits<Element>::value) - StorageUnit(1);
/// Pointer to array containing element
_war<StorageVecPointer> ptr_;
/// Offset (in units of elements) from pointer.
///
/// Invariant: must always be in range [0, kElementsPerVector)
int offset_;
/// Element may be stored across 2 storage unit.
/// Low storage unit index in StorageVec
/// High storage unit index in StorageVec
int low_storage_unit_idx_;
int high_storage_unit_idx_;
/// Full Mask to extract the entire element
uint64_t full_element_mask_;
/// Mask to extract the Element from Low storage unit and High storage unit.
StorageUnit low_storage_mask_;
StorageUnit high_storage_mask_;
/// Start bit index inside the storage unit.
int start_bit_idx_;
private:
CUTLASS_HOST_DEVICE
void update_element_status() {
int num_bits = offset_ * sizeof_bits<Element>::value;
start_bit_idx_ = num_bits % sizeof_bits<StorageUnit>::value;
low_storage_unit_idx_ = num_bits / sizeof_bits<StorageUnit>::value;
high_storage_unit_idx_ = sizeof_bits<StorageUnit>::value - (start_bit_idx_) < sizeof_bits<Element>::value
? low_storage_unit_idx_ + 1 : low_storage_unit_idx_;
full_element_mask_ = uint64_t(kMask) << start_bit_idx_;
low_storage_mask_ = StorageUnit(full_element_mask_ & ~StorageUnit(0));
high_storage_mask_ = StorageUnit((full_element_mask_ >> sizeof_bits<StorageUnit>::value) & ~StorageUnit(0));
}
public:
CUTLASS_HOST_DEVICE
SubbyteReference(): ptr_(nullptr), offset_(0) { }
/// Constructor
CUTLASS_HOST_DEVICE
SubbyteReference(
Element *ptr, /// pointer to memory
int64_t offset /// logical offset in units of Element
):
ptr_(reinterpret_cast<StorageVecPointer>(ptr)),
offset_(0) {
int64_t offset_in_vectors = offset / kElementsPerVector;
int64_t offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = int(offset_in_elements);
update_element_status();
}
/// Constructor
CUTLASS_HOST_DEVICE
SubbyteReference(
Element *ptr = nullptr
): SubbyteReference(ptr, 0) { }
/// Gets StorageVec pointer
CUTLASS_HOST_DEVICE
StorageVecPointer storage_pointer() const {
return ptr_;
}
/// Gets StorageVec pointer
CUTLASS_HOST_DEVICE
Element * operator&() const {
return reinterpret_cast<Element *>(ptr_);
}
/// Gets element offset within StorageVec vector
CUTLASS_HOST_DEVICE
int element_offset() const {
return offset_;
}
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
Element get() const {
StorageUnit low_bits = (*ptr_)[low_storage_unit_idx_] & low_storage_mask_;
StorageUnit high_bits = low_storage_unit_idx_ != high_storage_unit_idx_ ? (*ptr_)[high_storage_unit_idx_] & high_storage_mask_ : 0;
uint64_t full_item = ((uint64_t)high_bits << sizeof_bits<StorageUnit>::value) | low_bits;
uint8_t result = uint8_t(full_item >> start_bit_idx_);
return reinterpret_cast<Element const &>(result);
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference & set(Element const &x) {
uint64_t item = static_cast<uint64_t>((reinterpret_cast<uint8_t const &>(x) & kMask)) << start_bit_idx_;
StorageUnit low_new_bits = StorageUnit(item & ~StorageUnit(0));
StorageUnit high_new_bits = StorageUnit(item >> sizeof_bits<StorageUnit>::value);
StorageUnit const kLowUpdateMask = StorageUnit((~full_element_mask_) & (~StorageUnit(0)));
StorageUnit const kHighUpdateMask = StorageUnit(((~full_element_mask_) >> sizeof_bits<StorageUnit>::value) & (~StorageUnit(0)));
#if defined(__CUDA_ARCH__)
//
// Homebrew read-modify-write
//
if(high_storage_unit_idx_ != low_storage_unit_idx_){
/// Only need update 2 storage unit at once.
/// consider misaligned address issue, we need to do atomicCAS twice
StorageUnit original_low_bits, original_high_bits, update_low_bits, update_high_bits;
do {
original_low_bits = ((*ptr_)[low_storage_unit_idx_]);
update_low_bits = (original_low_bits & kLowUpdateMask) | low_new_bits;
original_low_bits = atomicCAS(&((*ptr_)[low_storage_unit_idx_]), original_low_bits, update_low_bits);
} while (update_low_bits != original_low_bits);
do {
original_high_bits = ((*ptr_)[high_storage_unit_idx_]);
update_high_bits = (original_high_bits & kHighUpdateMask) | high_new_bits;
original_high_bits = atomicCAS(&((*ptr_)[high_storage_unit_idx_]), original_high_bits, update_high_bits);
} while (update_high_bits != original_high_bits);
}
else {
/// Only need update 1 storage unit.
StorageUnit original, updated;
do {
original = ((*ptr_)[low_storage_unit_idx_]);
updated = (original & kLowUpdateMask) | low_new_bits;
original = atomicCAS(&((*ptr_)[low_storage_unit_idx_]), original, updated);
} while (updated != original);
}
#else
StorageUnit update_low_bits = ((*ptr_)[low_storage_unit_idx_] & kLowUpdateMask) | low_new_bits;
StorageUnit update_high_bits = ((*ptr_)[high_storage_unit_idx_] & kHighUpdateMask) | high_new_bits;
(*ptr_)[low_storage_unit_idx_] = update_low_bits;
if(low_storage_unit_idx_ != high_storage_unit_idx_)
(*ptr_)[high_storage_unit_idx_] = update_high_bits;
#endif
return *this;
}
////
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
operator Element() const {
return get();
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference &operator=(Element const & x) {
return set(x);
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference &operator=(SubbyteReference const & x) {
return set(x.get());
}
/// Stores an element to memory
CUTLASS_HOST_DEVICE
SubbyteReference &operator=(
ConstSubbyteReference<Element, StorageVec> const &x) {
return set(x.get());
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator+=(int offset) {
offset += offset_;
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
update_element_status();
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator+=(long long offset) {
offset += offset_;
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
update_element_status();
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator-=(int offset) {
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
update_element_status();
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
SubbyteReference &operator-=(long long offset) {
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
update_element_status();
return *this;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator+(int offset) const {
SubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator+(long long offset) const {
SubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator-(int offset) const {
SubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
SubbyteReference operator-=(long long offset) const {
SubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Computes the difference in elements between references
CUTLASS_HOST_DEVICE
ptrdiff_t operator-(SubbyteReference ref) const {
return (ptr_ - ref.ptr_) * kElementsPerVector + (offset_ - ref.offset_);
}
/// Explicit cast to int
CUTLASS_HOST_DEVICE
explicit operator int() const {
return int(get());
}
/// Explicit cast to signed 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator int64_t() const {
return int64_t(get());
}
/// Explicit cast to unsigned 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator uint64_t() const {
return uint64_t(get());
}
/// Explicit cast to float
CUTLASS_HOST_DEVICE
explicit operator float() const {
return float(get());
}
/// Explicit cast to double
CUTLASS_HOST_DEVICE
explicit operator double() const {
return double(get());
}
};
template<typename T> using _war = T;
template <
typename Element_, /// CUTLASS numeric element type.
typename Storage_ /// Underlying storage type. Must be able to hold an integer
>
class ConstSubbyteReference<Element_, Storage_,
typename platform::enable_if<sizeof_bits<Storage_>::value % sizeof_bits<Element_>::value != 0>::type> {
public:
using Element = Element_;
///! Note: Storage unit could not be divisibale by Element,
/// Type element may be stored across 2 storage units, so need a storage vector to hold integer
/// number of objects of type Element.
using StorageUnit = Storage_;
static int const kBitsStoredVec = cutlass::lcm_cxx11(sizeof_bits<Element>::value, sizeof_bits<StorageUnit>::value);
static int const kNumStorageUnitPerStoredVec = kBitsStoredVec / sizeof_bits<StorageUnit>::value;
using StorageVec = StorageUnit[kNumStorageUnitPerStoredVec];
using StorageVecPointer = StorageVec const *;
using CudaAtomicType = typename platform::conditional<
sizeof_bits<StorageUnit>::value == 16,
uint32_t,
uint64_t
>::type;
static_assert(sizeof_bits<Element>::value <= sizeof_bits<StorageVec>::value,
"Size of Element must not be greater than StorageVec.");
static_assert(!(sizeof_bits<StorageVec>::value % sizeof_bits<Element>::value),
"StorageVec must be divisible by Element");
private:
///! Number of elements per storage vector
int const kElementsPerVector = sizeof_bits<StorageVec>::value / sizeof_bits<Element>::value;
///! Bit mask for storage unit.
StorageUnit const kMask = (StorageUnit(1) << sizeof_bits<Element>::value) - StorageUnit(1);
/// Pointer to array containing element
_war<StorageVecPointer> ptr_;
/// Offset (in units of elements) from pointer.
///
/// Invariant: must always be in range [0, kElementsPerVector)
int offset_;
/// Element may be stored across 2 storage unit.
/// Low storage unit index in StorageVec
/// High storage unit index in StorageVec
int low_storage_unit_idx_;
int high_storage_unit_idx_;
/// Full Mask to extract the entire element
uint64_t full_element_mask_;
/// Mask to extract the Element from Low storage unit and High storage unit.
StorageUnit low_storage_mask_;
StorageUnit high_storage_mask_;
/// Start bit index inside the storage unit.
int start_bit_idx_;
private:
CUTLASS_HOST_DEVICE
void update_element_status() {
int num_bits = offset_ * sizeof_bits<Element>::value;
start_bit_idx_ = num_bits % sizeof_bits<StorageUnit>::value;
low_storage_unit_idx_ = num_bits / sizeof_bits<StorageUnit>::value;
high_storage_unit_idx_ = sizeof_bits<StorageUnit>::value - (start_bit_idx_) < sizeof_bits<Element>::value
? low_storage_unit_idx_ + 1 : low_storage_unit_idx_;
full_element_mask_ = uint64_t(kMask) << start_bit_idx_;
low_storage_mask_ = StorageUnit(full_element_mask_ & ~StorageUnit(0));
high_storage_mask_ = StorageUnit((full_element_mask_ >> sizeof_bits<StorageUnit>::value) & ~StorageUnit(0));
}
public:
CUTLASS_HOST_DEVICE
ConstSubbyteReference(): ptr_(nullptr), offset_(0) { }
/// Constructor
CUTLASS_HOST_DEVICE
ConstSubbyteReference(
Element const *ptr, /// pointer to memory
int64_t offset /// logical offset in units of Element
):
ptr_(reinterpret_cast<StorageVecPointer>(ptr)),
offset_(0) {
int64_t offset_in_vectors = offset / kElementsPerVector;
int64_t offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = int(offset_in_elements);
update_element_status();
}
/// Constructor
CUTLASS_HOST_DEVICE
ConstSubbyteReference(
Element *ptr = nullptr
): ConstSubbyteReference(ptr, 0) { }
/// Gets storage pointer
CUTLASS_HOST_DEVICE
StorageVecPointer storage_pointer() const {
return ptr_;
}
/// Gets element offset within storage vector
CUTLASS_HOST_DEVICE
int element_offset() const {
return offset_;
}
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
Element get() const {
StorageUnit low_bits = (*ptr_)[low_storage_unit_idx_] & low_storage_mask_;
StorageUnit high_bits = low_storage_unit_idx_ != high_storage_unit_idx_ ? (*ptr_)[high_storage_unit_idx_] & high_storage_mask_ : 0;
uint64_t full_item = ((uint64_t)high_bits << sizeof_bits<StorageUnit>::value) | low_bits;
uint8_t result = uint8_t(full_item >> start_bit_idx_);
return reinterpret_cast<Element const &>(result);
}
/// Unpacks an element from memory
CUTLASS_HOST_DEVICE
operator Element() const {
return get();
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator+=(int offset) {
offset += offset_;
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
update_element_status();
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator+=(long long offset) {
offset += offset_;
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ += offset_in_vectors;
offset_ = offset_in_elements;
update_element_status();
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator-=(int offset) {
int offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = offset % kElementsPerVector;
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
update_element_status();
return *this;
}
/// Adds an offset in units of elements to the reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference &operator-=(long long offset) {
long long offset_in_vectors = offset / kElementsPerVector;
int offset_in_elements = int(offset % kElementsPerVector);
ptr_ -= offset_in_vectors;
offset_ -= offset_in_elements;
if (offset_ < 0) {
offset_ += kElementsPerVector;
--ptr_;
}
update_element_status();
return *this;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator+(int offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator+(long long offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref += offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator-(int offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Returns a reference to an element with a given offset from the current reference
CUTLASS_HOST_DEVICE
ConstSubbyteReference operator-=(long long offset) const {
ConstSubbyteReference ref(ptr_, offset_);
ref -= offset;
return ref;
}
/// Computes the difference in elements between references
CUTLASS_HOST_DEVICE
ptrdiff_t operator-(ConstSubbyteReference ref) const {
return (ptr_ - ref.ptr_) * kElementsPerVector + (offset_ - ref.offset_);
}
/// Explicit cast to int
CUTLASS_HOST_DEVICE
explicit operator int() const {
return int(get());
}
/// Explicit cast to signed 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator int64_t() const {
return int64_t(get());
}
/// Explicit cast to unsigned 64-bit integer
CUTLASS_HOST_DEVICE
explicit operator uint64_t() const {
return uint64_t(get());
}
/// Explicit cast to float
CUTLASS_HOST_DEVICE
explicit operator float() const {
return float(get());
}
/// Explicit cast to double
CUTLASS_HOST_DEVICE
explicit operator double() const {
return double(get());
}
};
/////////////////////////////////////////////////////////////////////////////////////////////////
template <typename Element, bool subbyte = (sizeof_bits<Element>::value < 8)>
struct ReferenceFactory;
template <typename Element>
struct ReferenceFactory<Element, false> {
///! Number of elements per storage vector
static int const kElementsPerVector = 1;
CUTLASS_HOST_DEVICE
static Element &get(Element *ptr, int64_t offset) {
return ptr[offset];
}
CUTLASS_HOST_DEVICE
static Element const &get(Element const *ptr, int64_t offset) {
return ptr[offset];
}
CUTLASS_HOST_DEVICE
static Element *add_pointer_offset(Element *ptr, int64_t offset) {
return ptr + offset;
}
CUTLASS_HOST_DEVICE
static Element const *add_pointer_offset(Element const *ptr, int64_t offset) {
return ptr + offset;
}
};
template <typename Element>
struct ReferenceFactory<Element, true> {
//
// Static methods
//
CUTLASS_HOST_DEVICE
static SubbyteReference<Element> get(Element *ptr, int64_t offset) {
return SubbyteReference<Element>(ptr, offset);
}
CUTLASS_HOST_DEVICE
static ConstSubbyteReference<Element> get(Element const *ptr,
int64_t offset) {
return ConstSubbyteReference<Element>(ptr, offset);
}
/// Helper to add an offset in number of elements, assuming this offset is divisible
/// by the vector size.
CUTLASS_HOST_DEVICE
static Element *add_pointer_offset(Element *ptr, int64_t offset_in_elements) {
return ptr + offset_in_elements * sizeof_bits<Element>::value / sizeof(Element) / 8;
}
/// Helper to add an offset in number of elements, assuming this offset is divisible
/// by the vector size.
CUTLASS_HOST_DEVICE
static Element const *add_pointer_offset(Element const *ptr, int64_t offset_in_elements) {
return ptr + offset_in_elements * sizeof_bits<Element>::value / sizeof(Element) / 8;
}
};
/////////////////////////////////////////////////////////////////////////////////////////////////
} // namespace cutlass