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FP8 enablement - add a pseudorandom number generator, add conversion methods (#708)

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* Add basic fp8 definitions and prn-generator

* Format

* Add fp8<->fp32 type_convert

* Format

* Split type_convert and cast_to/from_f8

* Format

* Minor fix

* Minor fix

* Move fp8 utils to a separate header

* Add elementwise ops

* Add fp8_convert_sr

* Format

* Add element op

* Eliminate magic numbers

* Split f8_convert_sr in host and device

* Format

* Add some constexpr

* Add a datatype test

* Format

* Another format

* Add fp8<->fp16 tests

* Update type_converts

* Format

* Add fp16 casting functions

* Format

* Use seed as a runtime arg

* Use element location for PRNG

* Format

* Add fp8<->fp16 to PassThrough element op

* Clean up

* Merge host and device implementations

* Add comments on rounding modes

* Remove leftover code

* Put type_converts into a separate header

* Put random number gen to a separate header

* Rearrange f8_utils' namespaces

* Refactor type_convert.hpp

* Move f8_t definition

[ROCm/composable_kernel commit: f0c620c42e]
This commit is contained in:
Rostyslav Geyyer
2023-06-19 11:20:35 -05:00
committed by GitHub
parent 9c2487d2a0
commit 09bc04e7a4
11 changed files with 743 additions and 145 deletions
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48
include/ck/tensor_operation/gpu/element/unary_element_wise_operation.hpp
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@@ -6,6 +6,7 @@
#include "ck/utility/data_type.hpp"
#include "ck/utility/math.hpp"
#include "ck/utility/math_v2.hpp"
#include "ck/utility/type_convert.hpp"
namespace ck {
namespace tensor_operation {
@@ -81,6 +82,36 @@ struct PassThrough
y = x;
}
#endif
template <>
__host__ __device__ void operator()<f8_t, f8_t>(f8_t& y, const f8_t& x) const
{
y = x;
}
template <>
__host__ __device__ void operator()<float, f8_t>(float& y, const f8_t& x) const
{
y = type_convert<float>(x);
}
template <>
__host__ __device__ void operator()<f8_t, float>(f8_t& y, const float& x) const
{
y = type_convert<f8_t>(x);
}
template <>
__host__ __device__ void operator()<half_t, f8_t>(half_t& y, const f8_t& x) const
{
y = type_convert<half_t>(x);
}
template <>
__host__ __device__ void operator()<f8_t, half_t>(f8_t& y, const half_t& x) const
{
y = type_convert<f8_t>(x);
}
};
struct UnaryConvert
@@ -109,6 +140,23 @@ struct ConvertBF16RTN
}
};
struct ConvertF8SR
{
// convert to fp8 using stochastic rounding (SR)
template <typename Y, typename X>
__host__ __device__ void operator()(Y& y, const X& x) const
{
// check Y datatype
static_assert(is_same<Y, f8_t>::value, "Data type is not supported by this operation!");
// check X datatype
static_assert(is_same<X, float>::value || is_same<X, half_t>::value,
"Data type is not supported by this operation!");
y = f8_convert_sr<Y>(x);
}
};
struct Scale
{
__host__ __device__ Scale(float scale) : scale_(scale) {}

1
include/ck/utility/common_header.hpp
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@@ -24,6 +24,7 @@
#include "ck/utility/tuple.hpp"
#include "ck/utility/tuple_helper.hpp"
#include "ck/utility/type.hpp"
#include "ck/utility/type_convert.hpp"
#include "ck/utility/magic_division.hpp"
#include "ck/utility/c_style_pointer_cast.hpp"
#include "ck/utility/is_known_at_compile_time.hpp"

177
include/ck/utility/data_type.hpp
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@@ -12,6 +12,7 @@ using half_t = _Float16;
#ifdef CK_EXPERIMENTAL_BIT_INT_EXTENSION_INT4
using int4_t = _BitInt(4);
#endif
using f8_t = uint8_t;
// vector_type
template <typename T, index_t N>
@@ -142,6 +143,13 @@ struct scalar_type<int4_t>
};
#endif
template <>
struct scalar_type<f8_t>
{
using type = f8_t;
static constexpr index_t vector_size = 1;
};
//
template <typename T>
struct vector_type<T, 1>
@@ -944,151 +952,13 @@ using int8x16_t = typename vector_type<int8_t, 16>::type;
using int8x32_t = typename vector_type<int8_t, 32>::type;
using int8x64_t = typename vector_type<int8_t, 64>::type;
// Convert X to Y
template <typename Y, typename X>
__host__ __device__ constexpr Y type_convert(X x)
{
static_assert(!std::is_reference_v<Y> && !std::is_reference_v<X>);
return static_cast<Y>(x);
}
// convert bfp16 to fp32
template <>
inline __host__ __device__ constexpr float type_convert<float, bhalf_t>(bhalf_t x)
{
union
{
uint32_t int32;
float fp32;
} u = {uint32_t(x) << 16};
return u.fp32;
}
// convert fp32 to bfp16
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, float>(float x)
{
union
{
float fp32;
uint32_t int32;
} u = {x};
return uint16_t(u.int32 >> 16);
}
// convert bfp16 to fp16 via fp32
template <>
inline __host__ __device__ constexpr half_t type_convert<half_t, bhalf_t>(bhalf_t x)
{
float x_fp32 = type_convert<float>(x);
return static_cast<half_t>(x_fp32);
}
// convert fp16 to bfp16 via fp32
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, half_t>(half_t x)
{
float x_fp32 = static_cast<float>(x);
return type_convert<bhalf_t>(x_fp32);
}
// convert bfp16 to int32 via fp32
template <>
inline __host__ __device__ constexpr int32_t type_convert<int32_t, bhalf_t>(bhalf_t x)
{
float x_fp32 = type_convert<float>(x);
return static_cast<int32_t>(x_fp32);
}
// convert int32 to bfp16 via fp32
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, int32_t>(int32_t x)
{
float x_fp32 = static_cast<float>(x);
return type_convert<bhalf_t>(x_fp32);
}
// convert bfp16 to int8 via fp32
template <>
inline __host__ __device__ constexpr int8_t type_convert<int8_t, bhalf_t>(bhalf_t x)
{
float x_fp32 = type_convert<float>(x);
return static_cast<int8_t>(x_fp32);
}
// convert int8 to bfp16 via fp32
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, int8_t>(int8_t x)
{
float x_fp32 = static_cast<float>(x);
return type_convert<bhalf_t>(x_fp32);
}
// Declare a template function for bf16 conversion using RTN
template <typename Y, typename X>
__host__ __device__ constexpr Y bf16_convert_rtn(X x);
// Convert fp32 to bf16 with RTN if higher precision is needed
template <>
inline __host__ __device__ constexpr bhalf_t bf16_convert_rtn<bhalf_t, float>(float x)
{
union
{
float fp32;
uint32_t int32;
} u = {x};
// When the exponent bits are not all 1s, then the value is zero, normal,
// or subnormal. We round the bfloat16 mantissa up by adding 0x7FFF, plus
// 1 if the least significant bit of the bfloat16 mantissa is 1 (odd).
// This causes the bfloat16's mantissa to be incremented by 1 if the 16
// least significant bits of the float mantissa are greater than 0x8000,
// or if they are equal to 0x8000 and the least significant bit of the
// bfloat16 mantissa is 1 (odd). This causes it to be rounded to even when
// the lower 16 bits are exactly 0x8000. If the bfloat16 mantissa already
// has the value 0x7f, then incrementing it causes it to become 0x00 and
// the exponent is incremented by one, which is the next higher FP value
// to the unrounded bfloat16 value. When the bfloat16 value is subnormal
// with an exponent of 0x00 and a mantissa of 0x7f, it may be rounded up
// to a normal value with an exponent of 0x01 and a mantissa of 0x00.
// When the bfloat16 value has an exponent of 0xFE and a mantissa of 0x7F,
// incrementing it causes it to become an exponent of 0xFF and a mantissa
// of 0x00, which is Inf, the next higher value to the unrounded value.
bool flag0 = ~u.int32 & 0x7f800000;
// When all of the exponent bits are 1, the value is Inf or NaN.
// Inf is indicated by a zero mantissa. NaN is indicated by any nonzero
// mantissa bit. Quiet NaN is indicated by the most significant mantissa
// bit being 1. Signaling NaN is indicated by the most significant
// mantissa bit being 0 but some other bit(s) being 1. If any of the
// lower 16 bits of the mantissa are 1, we set the least significant bit
// of the bfloat16 mantissa, in order to preserve signaling NaN in case
// the bfloat16's mantissa bits are all 0.
bool flag1 = !flag0 && (u.int32 & 0xffff);
u.int32 += flag0 ? 0x7fff + ((u.int32 >> 16) & 1) : 0; // Round to nearest, round to even
u.int32 |= flag1 ? 0x10000 : 0x0; // Preserve signaling NaN
return uint16_t(u.int32 >> 16);
}
// convert fp16 to bfp16 via fp32 with RTN if higher precision is needed
template <>
inline __host__ __device__ constexpr bhalf_t bf16_convert_rtn<bhalf_t, half_t>(half_t x)
{
float x_fp32 = static_cast<float>(x);
return bf16_convert_rtn<bhalf_t>(x_fp32);
}
// f8
using f8x2_t = typename vector_type<f8_t, 2>::type;
using f8x4_t = typename vector_type<f8_t, 4>::type;
using f8x8_t = typename vector_type<f8_t, 8>::type;
using f8x16_t = typename vector_type<f8_t, 16>::type;
using f8x32_t = typename vector_type<f8_t, 32>::type;
using f8x64_t = typename vector_type<f8_t, 64>::type;
template <typename T>
struct NumericLimits
@@ -1136,4 +1006,21 @@ struct NumericLimits<int4_t>
};
#endif // CK_EXPERIMENTAL_BIT_INT_EXTENSION_INT4
template <>
struct NumericLimits<f8_t>
{
static constexpr uint8_t binary_min = 0x08; // 0b00001000
static constexpr uint8_t binary_max = 0x77; // 0b01110111
static constexpr uint8_t binary_lowest = 0xF7; // 0b11110111
static constexpr uint8_t binary_qnan = 0x80; // 0b10000000
__host__ __device__ static constexpr f8_t Min() { return bit_cast<f8_t>(binary_min); }
__host__ __device__ static constexpr f8_t Max() { return bit_cast<f8_t>(binary_max); }
__host__ __device__ static constexpr f8_t Lowest() { return bit_cast<f8_t>(binary_lowest); }
__host__ __device__ static constexpr f8_t QuietNaN() { return bit_cast<f8_t>(binary_qnan); }
};
} // namespace ck

250
include/ck/utility/f8_utils.hpp Normal file
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@@ -0,0 +1,250 @@
// SPDX-License-Identifier: MIT
// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
#pragma once
#include "ck/utility/data_type.hpp"
namespace ck {
// fp8 rounding modes
// use standard for rounding to nearest, the faster one
// use stochastic for stochastic rounding, helps to avoid error accumulation
enum class f8_rounding_mode
{
standard,
stochastic
};
} // namespace ck
namespace ck::utils {
namespace {
template <typename T, bool negative_zero_nan, bool clip, bool stoch>
__host__ __device__ f8_t run_cast_to_f8(T x, uint32_t rng)
{
// check data type
constexpr bool is_half = std::is_same<T, half_t>::value;
constexpr bool is_float = std::is_same<T, float>::value;
// fp8 exponent/mantissa layout
constexpr int f8_exp = 4;
constexpr int f8_mant = 3;
// resulting type exponent/mantissa layout
constexpr int type_exp = is_half ? 5 : 8;
constexpr int type_mant = is_half ? 10 : 23;
int exponent;
uint32_t head, mantissa, sign;
// nan code is same for float and half
constexpr uint8_t nan_code = 0x80;
constexpr uint32_t nan_mask = is_half ? 0x7C00 : 0x7F800000;
// convert to bitwise
typedef typename std::conditional<std::is_same<T, half_t>::value, uint16_t, uint32_t>::type
T_bitwise;
T_bitwise x_bitwise = *(reinterpret_cast<T_bitwise*>(&x));
// unpack the input, depends on datatype
if constexpr(is_float)
{
head = x_bitwise & 0xFF800000;
mantissa = x_bitwise & 0x7FFFFF;
exponent = (head >> type_mant) & 0xFF;
sign = head >> (type_exp + type_mant);
}
else if constexpr(is_half)
{
head = x_bitwise & 0xFC00;
mantissa = x_bitwise & 0x3FF;
exponent = (head >> type_mant) & 0x1F;
sign = head >> (type_exp + type_mant);
}
uint32_t signed_inf = (sign << (type_exp + type_mant)) + (((1 << type_exp) - 1) << type_mant);
uint32_t drop_mask = (1 << (type_mant - f8_mant)) - 1;
constexpr int max_exp = (1 << f8_exp) - (negative_zero_nan ? 1 : 2);
constexpr int exp_low_cutoff =
(1 << (type_exp - 1)) - (1 << (f8_exp - 1)) + 1 - (negative_zero_nan ? 1 : 0);
if constexpr(negative_zero_nan)
{
if((x_bitwise & nan_mask) == nan_mask)
return nan_code;
}
else
{
if((x_bitwise & nan_mask) == nan_mask)
return signed_inf + (mantissa != 0 ? 1 : 0);
}
// check if x is 0.0
if(x_bitwise == 0)
return 0;
exponent -= exp_low_cutoff - 1;
if(exponent <= 0)
drop_mask = (1 << (type_mant - f8_mant + 1 - exponent)) - 1;
mantissa += 1 << type_mant;
// apply random number if needed
mantissa += (stoch ? rng : mantissa) & drop_mask;
if(mantissa >= (2 << type_mant))
{
mantissa >>= 1;
exponent++;
}
mantissa >>= (type_mant - f8_mant);
// check negative exponent
if(exponent <= 0)
{
if(x_bitwise == 0)
return 0;
else
{
// subnormal range; represented by a subnormal float8 (exponent 0)
// and involves loss of accuracy
mantissa >>= 1 - exponent;
exponent = 0;
}
}
// above range: quantize to maximum possible float of the same sign
else if(exponent > max_exp)
{
if(clip)
{
mantissa = (1 << f8_mant) - 1;
exponent = max_exp;
}
else
{
return signed_inf;
}
}
// check if x is 0.0 or -0.0
if(exponent == 0 && mantissa == 0)
return negative_zero_nan ? 0 : (sign << (f8_exp + f8_mant));
mantissa &= (1 << f8_mant) - 1;
return (sign << (f8_exp + f8_mant)) | (exponent << f8_mant) | mantissa;
}
template <typename T, bool negative_zero_nan>
__host__ __device__ T run_cast_from_f8(f8_t x)
{
// check data type
constexpr bool is_half = std::is_same<T, half_t>::value;
constexpr bool is_float = std::is_same<T, float>::value;
// fp8 exponent/mantissa layout
constexpr int f8_exp = 4;
constexpr int f8_mant = 3;
// resulting type exponent/mantissa layout
constexpr int type_exp = is_half ? 5 : 8;
constexpr int type_mant = is_half ? 10 : 23;
// prepare the codes
constexpr uint8_t nan_code = 0x80;
T fInf, fNegInf, fNaN, fNeg0;
if constexpr(is_half)
{
constexpr uint16_t ihInf = 0x7C00;
constexpr uint16_t ihNegInf = 0xFC00;
constexpr uint16_t ihNaN = 0x7C01;
constexpr uint16_t ihNeg0 = 0x8000;
fInf = *(reinterpret_cast<const half_t*>(&ihInf));
fNegInf = *(reinterpret_cast<const half_t*>(&ihNegInf));
fNaN = *(reinterpret_cast<const half_t*>(&ihNaN));
fNeg0 = *(reinterpret_cast<const half_t*>(&ihNeg0));
}
else if constexpr(is_float)
{
constexpr uint32_t ifInf = 0x7F800000;
constexpr uint32_t ifNegInf = 0xFF800000;
constexpr uint32_t ifNaN = 0x7F800001;
constexpr uint32_t ifNeg0 = 0x80000000;
fInf = *(reinterpret_cast<const float*>(&ifInf));
fNegInf = *(reinterpret_cast<const float*>(&ifNegInf));
fNaN = *(reinterpret_cast<const float*>(&ifNaN));
fNeg0 = *(reinterpret_cast<const float*>(&ifNeg0));
}
// unpack the input
uint32_t sign = x >> (f8_exp + f8_mant);
uint32_t mantissa = x & ((1 << f8_mant) - 1);
int exponent = (x & 0x7F) >> f8_mant;
constexpr int exp_low_cutoff =
(1 << (type_exp - 1)) - (1 << (f8_exp - 1)) + 1 - (negative_zero_nan ? 1 : 0);
typename std::conditional<std::is_same<T, half_t>::value, uint16_t, uint32_t>::type retval;
if constexpr(negative_zero_nan)
{
if(x == nan_code)
return fNaN;
}
else
{
if(x == nan_code)
return fNeg0;
if(exponent == ((1 << f8_exp) - 1))
return (mantissa == 0) ? (sign ? fNegInf : fInf) : fNaN;
}
// subnormal input
if(exponent == 0)
{
// guaranteed mantissa!=0 since cases 0x0 and 0x80 are handled above
int sh = 1 + __builtin_clz(mantissa) - ((1 + type_exp + type_mant) - f8_mant);
mantissa <<= sh;
mantissa &= ((1 << f8_mant) - 1);
exponent += 1 - sh;
}
exponent += exp_low_cutoff - 1;
mantissa <<= type_mant - f8_mant;
// subnormal output (occurs when T=half, we=5, negative_zero_nan=true)
if(exponent <= 0)
{
mantissa |= 1 << type_mant;
mantissa >>= 1 - exponent;
exponent = 0;
}
retval = (sign << (type_exp + type_mant)) | (exponent << type_mant) | mantissa;
return *(reinterpret_cast<const T*>(&retval));
}
} // namespace
template <typename T, bool negative_zero_nan, bool clip, bool stoch>
__host__ __device__ f8_t cast_to_f8(T x, uint32_t rng)
{
// check datatype
constexpr bool is_half = std::is_same<T, half_t>::value;
constexpr bool is_float = std::is_same<T, float>::value;
static_assert(is_half || is_float, "Only half and float can be casted to f8.");
return run_cast_to_f8<T, negative_zero_nan, clip, stoch>(x, rng);
}
template <typename T, bool negative_zero_nan>
__host__ __device__ T cast_from_f8(f8_t x)
{
// check datatype
constexpr bool is_half = std::is_same<T, half_t>::value;
constexpr bool is_float = std::is_same<T, float>::value;
static_assert(is_half || is_float, "only half and float are supported.");
// check if x is 0.0
if(x == 0)
return static_cast<T>(0);
return run_cast_from_f8<T, negative_zero_nan>(x);
}
} // namespace ck::utils

1
include/ck/utility/inner_product.hpp
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@@ -3,6 +3,7 @@
#pragma once
#include "data_type.hpp"
#include "type_convert.hpp"
namespace ck {

53
include/ck/utility/random_gen.hpp Normal file
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@@ -0,0 +1,53 @@
// SPDX-License-Identifier: MIT
// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
#pragma once
namespace ck {
// Pseudo random number generator
// version for fp32
template <typename T, uint32_t seed_t, std::enable_if_t<std::is_same<float, T>{}, bool> = false>
__host__ __device__ uint32_t prand_generator(index_t id, T val, uint32_t seed = seed_t)
{
uint32_t x = *(reinterpret_cast<uint32_t*>(&val));
uint32_t drop_bits = uint32_t(x) & 0xFFFFu;
drop_bits ^= x >> 16;
drop_bits = ((drop_bits & 31) << 11) | (drop_bits >> 5);
drop_bits *= 0x7000149;
// NOTE: If id is in 64 bit, we are only using lower 32 bit.
// So, it can have an effect of using same id for multiple elements when the id is very
// large!
uint32_t rng = (drop_bits ^ 0x13371337 ^ (id * 229791) ^ seed);
return rng;
}
// version for fp16
template <typename T, uint32_t seed_t, std::enable_if_t<std::is_same<half_t, T>{}, bool> = false>
__host__ __device__ uint32_t prand_generator(index_t id, T val, uint32_t seed = seed_t)
{
uint16_t x = *(reinterpret_cast<uint16_t*>(&val));
uint32_t drop_bits = uint32_t(x) & 0xFFFFu;
drop_bits = ((drop_bits & 31) << 11) | (drop_bits >> 5);
drop_bits *= 0x7000149;
// NOTE: If id is in 64 bit, we are only using lower 32 bit.
// So, it can have an effect of using same id for multiple elements when the id is very
// large!
uint32_t rng = (drop_bits ^ 0x13371337 ^ (id * 229791) ^ seed);
return rng;
}
// return 0 if data is not fp16 or fp32
template <typename T,
uint32_t seed_t,
std::enable_if_t<!(std::is_same<float, T>{} || std::is_same<half_t, T>{}), bool> = false>
__host__ __device__ uint32_t prand_generator(int id, T val, uint32_t seed = seed_t)
{
std::ignore = id;
std::ignore = val;
std::ignore = seed;
return 0;
}
} // namespace ck

1
include/ck/utility/reduction_operator.hpp
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@@ -6,6 +6,7 @@
#include "ck/ck.hpp"
#include "ck/utility/data_type.hpp"
#include "ck/utility/type.hpp"
#include "ck/utility/type_convert.hpp"
namespace ck {

230
include/ck/utility/type_convert.hpp Normal file
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@@ -0,0 +1,230 @@
// SPDX-License-Identifier: MIT
// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
#pragma once
#include "ck/utility/data_type.hpp"
#include "ck/utility/f8_utils.hpp"
#include "ck/utility/random_gen.hpp"
namespace ck {
// Convert X to Y
template <typename Y, typename X>
__host__ __device__ constexpr Y type_convert(X x)
{
static_assert(!std::is_reference_v<Y> && !std::is_reference_v<X>);
return static_cast<Y>(x);
}
// convert bfp16 to fp32
template <>
inline __host__ __device__ constexpr float type_convert<float, bhalf_t>(bhalf_t x)
{
union
{
uint32_t int32;
float fp32;
} u = {uint32_t(x) << 16};
return u.fp32;
}
// convert fp32 to bfp16
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, float>(float x)
{
union
{
float fp32;
uint32_t int32;
} u = {x};
return uint16_t(u.int32 >> 16);
}
// convert bfp16 to fp16 via fp32
template <>
inline __host__ __device__ constexpr half_t type_convert<half_t, bhalf_t>(bhalf_t x)
{
float x_fp32 = type_convert<float>(x);
return static_cast<half_t>(x_fp32);
}
// convert fp16 to bfp16 via fp32
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, half_t>(half_t x)
{
float x_fp32 = static_cast<float>(x);
return type_convert<bhalf_t>(x_fp32);
}
// convert bfp16 to int32 via fp32
template <>
inline __host__ __device__ constexpr int32_t type_convert<int32_t, bhalf_t>(bhalf_t x)
{
float x_fp32 = type_convert<float>(x);
return static_cast<int32_t>(x_fp32);
}
// convert int32 to bfp16 via fp32
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, int32_t>(int32_t x)
{
float x_fp32 = static_cast<float>(x);
return type_convert<bhalf_t>(x_fp32);
}
// convert bfp16 to int8 via fp32
template <>
inline __host__ __device__ constexpr int8_t type_convert<int8_t, bhalf_t>(bhalf_t x)
{
float x_fp32 = type_convert<float>(x);
return static_cast<int8_t>(x_fp32);
}
// convert int8 to bfp16 via fp32
template <>
inline __host__ __device__ constexpr bhalf_t type_convert<bhalf_t, int8_t>(int8_t x)
{
float x_fp32 = static_cast<float>(x);
return type_convert<bhalf_t>(x_fp32);
}
// convert fp32 to fp8
template <>
inline __host__ __device__ f8_t type_convert<f8_t, float>(float x)
{
constexpr bool negative_zero_nan = true;
constexpr bool clip = true;
constexpr f8_rounding_mode rm = f8_rounding_mode::standard;
constexpr uint32_t rng = 0;
return utils::cast_to_f8<float, negative_zero_nan, clip, (rm == f8_rounding_mode::stochastic)>(
x, rng);
}
// convert fp8 to fp32
template <>
inline __host__ __device__ float type_convert<float, f8_t>(f8_t x)
{
constexpr bool negative_zero_nan = true;
return utils::cast_from_f8<float, negative_zero_nan>(x);
}
// convert fp16 to fp8
template <>
inline __host__ __device__ f8_t type_convert<f8_t, half_t>(half_t x)
{
constexpr bool negative_zero_nan = true;
constexpr bool clip = true;
constexpr f8_rounding_mode rm = f8_rounding_mode::standard;
constexpr uint32_t rng = 0;
return utils::cast_to_f8<half_t, negative_zero_nan, clip, (rm == f8_rounding_mode::stochastic)>(
x, rng);
}
// convert fp8 to fp16
template <>
inline __host__ __device__ half_t type_convert<half_t, f8_t>(f8_t x)
{
constexpr bool negative_zero_nan = true;
return utils::cast_from_f8<half_t, negative_zero_nan>(x);
}
// Declare a template function for bf16 conversion using RTN
template <typename Y, typename X>
__host__ __device__ constexpr Y bf16_convert_rtn(X x);
// Convert fp32 to bf16 with RTN if higher precision is needed
template <>
inline __host__ __device__ constexpr bhalf_t bf16_convert_rtn<bhalf_t, float>(float x)
{
union
{
float fp32;
uint32_t int32;
} u = {x};
// When the exponent bits are not all 1s, then the value is zero, normal,
// or subnormal. We round the bfloat16 mantissa up by adding 0x7FFF, plus
// 1 if the least significant bit of the bfloat16 mantissa is 1 (odd).
// This causes the bfloat16's mantissa to be incremented by 1 if the 16
// least significant bits of the float mantissa are greater than 0x8000,
// or if they are equal to 0x8000 and the least significant bit of the
// bfloat16 mantissa is 1 (odd). This causes it to be rounded to even when
// the lower 16 bits are exactly 0x8000. If the bfloat16 mantissa already
// has the value 0x7f, then incrementing it causes it to become 0x00 and
// the exponent is incremented by one, which is the next higher FP value
// to the unrounded bfloat16 value. When the bfloat16 value is subnormal
// with an exponent of 0x00 and a mantissa of 0x7f, it may be rounded up
// to a normal value with an exponent of 0x01 and a mantissa of 0x00.
// When the bfloat16 value has an exponent of 0xFE and a mantissa of 0x7F,
// incrementing it causes it to become an exponent of 0xFF and a mantissa
// of 0x00, which is Inf, the next higher value to the unrounded value.
bool flag0 = ~u.int32 & 0x7f800000;
// When all of the exponent bits are 1, the value is Inf or NaN.
// Inf is indicated by a zero mantissa. NaN is indicated by any nonzero
// mantissa bit. Quiet NaN is indicated by the most significant mantissa
// bit being 1. Signaling NaN is indicated by the most significant
// mantissa bit being 0 but some other bit(s) being 1. If any of the
// lower 16 bits of the mantissa are 1, we set the least significant bit
// of the bfloat16 mantissa, in order to preserve signaling NaN in case
// the bfloat16's mantissa bits are all 0.
bool flag1 = !flag0 && (u.int32 & 0xffff);
u.int32 += flag0 ? 0x7fff + ((u.int32 >> 16) & 1) : 0; // Round to nearest, round to even
u.int32 |= flag1 ? 0x10000 : 0x0; // Preserve signaling NaN
return uint16_t(u.int32 >> 16);
}
// convert fp16 to bfp16 via fp32 with RTN if higher precision is needed
template <>
inline __host__ __device__ constexpr bhalf_t bf16_convert_rtn<bhalf_t, half_t>(half_t x)
{
float x_fp32 = static_cast<float>(x);
return bf16_convert_rtn<bhalf_t>(x_fp32);
}
// Declare a template function for fp8 conversion using SR
template <typename Y, typename X>
__host__ __device__ constexpr Y f8_convert_sr(X x);
// convert fp32 to fp8 with stochastic rounding
template <>
inline __host__ __device__ f8_t f8_convert_sr<f8_t, float>(float x)
{
constexpr bool negative_zero_nan = true;
constexpr bool clip = true;
constexpr f8_rounding_mode rm = f8_rounding_mode::stochastic;
constexpr int seed = 42;
// as thread id is not available on host, use 0 for prn generation
uint32_t rng = prand_generator<float, seed>(reinterpret_cast<uintptr_t>(&x), x);
return utils::cast_to_f8<float, negative_zero_nan, clip, (rm == f8_rounding_mode::stochastic)>(
x, rng);
}
// convert fp16 to fp8 with stochastic rounding
template <>
inline __host__ __device__ f8_t f8_convert_sr<f8_t, half_t>(half_t x)
{
constexpr bool negative_zero_nan = true;
constexpr bool clip = true;
constexpr f8_rounding_mode rm = f8_rounding_mode::stochastic;
constexpr int seed = 42;
// as thread id is not available on host, use 0 for prn generation
uint32_t rng = prand_generator<half_t, seed>(reinterpret_cast<uintptr_t>(&x), x);
return utils::cast_to_f8<half_t, negative_zero_nan, clip, (rm == f8_rounding_mode::stochastic)>(
x, rng);
}
} // namespace ck

1
library/include/ck/library/utility/host_tensor.hpp
View File

@@ -13,6 +13,7 @@
#include "ck/utility/data_type.hpp"
#include "ck/utility/span.hpp"
#include "ck/utility/type_convert.hpp"
#include "ck/library/utility/algorithm.hpp"
#include "ck/library/utility/ranges.hpp"

3
test/data_type/CMakeLists.txt
View File

@@ -2,3 +2,6 @@ if (USE_BITINT_EXTENSION_INT4)
add_gtest_executable(test_int4 int4.cpp)
target_link_libraries(test_int4 PRIVATE utility)
endif()
add_gtest_executable(test_fp8 fp8.cpp)
target_link_libraries(test_fp8 PRIVATE utility)

123
test/data_type/fp8.cpp Normal file
View File

@@ -0,0 +1,123 @@
// SPDX-License-Identifier: MIT
// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
#include "gtest/gtest.h"
#include "ck/utility/data_type.hpp"
#include "ck/utility/type_convert.hpp"
using ck::f8_convert_sr;
using ck::f8_t;
using ck::half_t;
using ck::type_convert;
TEST(FP8, NumericLimits)
{
EXPECT_EQ(ck::NumericLimits<f8_t>::Min(), 0x08);
EXPECT_EQ(ck::NumericLimits<f8_t>::Max(), 0x77);
EXPECT_EQ(ck::NumericLimits<f8_t>::Lowest(), 0xF7);
EXPECT_EQ(ck::NumericLimits<f8_t>::QuietNaN(), 0x80);
}
TEST(FP8, ConvertFP32Nearest)
{
// fix the tolerance value
float abs_tol = 1e-6;
// convert 0 float to fp8 and back, check if holds
ASSERT_NEAR(0.0f, type_convert<float>(type_convert<f8_t>(0.0f)), abs_tol);
// convert minimal float to fp8 and back, check if holds
ASSERT_NEAR(std::numeric_limits<float>::min(),
type_convert<float>(type_convert<f8_t>(std::numeric_limits<float>::min())),
abs_tol);
// convert maximal f8_t to float and check if equal to 240.0
ASSERT_NEAR(240.0f, type_convert<float>(type_convert<f8_t>(240.0f)), abs_tol);
// convert maximal float to fp8 and back, check if clipped to 240.0
ASSERT_NEAR(240.0f,
type_convert<float>(type_convert<f8_t>(std::numeric_limits<float>::max())),
abs_tol);
// convert inf float to f8_t and check if it is qNan
ASSERT_NEAR(0x80, type_convert<f8_t>(std::numeric_limits<float>::infinity()), abs_tol);
// positive float value to fp8 and back, check if holds
float pos_float = 0.0078125f;
ASSERT_NEAR(pos_float, type_convert<float>(type_convert<f8_t>(pos_float)), abs_tol);
// negative float value to fp8 and back, check if holds
float neg_float = -0.0156250f;
ASSERT_NEAR(neg_float, type_convert<float>(type_convert<f8_t>(neg_float)), abs_tol);
}
TEST(FP8, ConvertFP32Stochastic)
{
// fix the tolerance value
float abs_tol = 1e-6;
// convert 0 float to fp8 and back, check if holds
ASSERT_NEAR(0.0f, type_convert<float>(f8_convert_sr<f8_t>(0.0f)), abs_tol);
// convert minimal float to fp8 and back, check if holds
ASSERT_NEAR(std::numeric_limits<float>::min(),
type_convert<float>(f8_convert_sr<f8_t>(std::numeric_limits<float>::min())),
abs_tol);
// convert maximal f8_t to float and check if equal to 240.0
ASSERT_NEAR(240.0f, type_convert<float>(f8_convert_sr<f8_t>(240.0f)), abs_tol);
// convert maximal float to fp8 and back, check if clipped to 240.0
ASSERT_NEAR(240.0f,
type_convert<float>(f8_convert_sr<f8_t>(std::numeric_limits<float>::max())),
abs_tol);
// convert inf float to f8_t and check if it is qNan
ASSERT_NEAR(0x80, f8_convert_sr<f8_t>(std::numeric_limits<float>::infinity()), abs_tol);
// positive float value to fp8 and back, check if holds
float pos_float = 0.0078125f;
ASSERT_NEAR(pos_float, type_convert<float>(f8_convert_sr<f8_t>(pos_float)), abs_tol);
// negative float value to fp8 and back, check if holds
float neg_float = -0.0156250f;
ASSERT_NEAR(neg_float, type_convert<float>(f8_convert_sr<f8_t>(neg_float)), abs_tol);
}
TEST(FP8, ConvertFP16Nearest)
{
// fix the tolerance value
float abs_tol = 1e-3;
// convert 0 fp16 to fp8 and back, check if holds
ASSERT_NEAR(half_t{0.0}, type_convert<half_t>(type_convert<f8_t>(half_t{0.0})), abs_tol);
// convert minimal fp16 to fp8 and back, check if holds
ASSERT_NEAR(ck::NumericLimits<half_t>::Min(),
type_convert<half_t>(type_convert<f8_t>(ck::NumericLimits<half_t>::Min())),
abs_tol);
// convert maximal f8_t to fp16 and check if equal to 240.0
ASSERT_NEAR(half_t{240.0}, type_convert<half_t>(type_convert<f8_t>(half_t{240.0})), abs_tol);
// convert maximal fp16 to fp8 and back, check if clipped to 240.0
ASSERT_NEAR(half_t{240.0},
type_convert<half_t>(type_convert<f8_t>(ck::NumericLimits<half_t>::Max())),
abs_tol);
// convert QuietNaN fp16 to f8_t and check if it is QuietNaN
ASSERT_NEAR(0x80, type_convert<f8_t>(ck::NumericLimits<half_t>::QuietNaN()), abs_tol);
// positive fp16 value to fp8 and back, check if holds
half_t pos_half = half_t{0.0078125};
ASSERT_NEAR(pos_half, type_convert<half_t>(type_convert<f8_t>(pos_half)), abs_tol);
// negative fp16 value to fp8 and back, check if holds
half_t neg_half = half_t{-0.0156250};
ASSERT_NEAR(neg_half, type_convert<half_t>(type_convert<f8_t>(neg_half)), abs_tol);
}
TEST(FP8, ConvertFP16Stochastic)
{
// fix the tolerance value
float abs_tol = 1e-3;
// convert 0 fp16 to fp8 and back, check if holds
ASSERT_NEAR(half_t{0.0}, type_convert<half_t>(f8_convert_sr<f8_t>(half_t{0.0})), abs_tol);
// convert minimal fp16 to fp8 and back, check if holds
ASSERT_NEAR(ck::NumericLimits<half_t>::Min(),
type_convert<half_t>(f8_convert_sr<f8_t>(ck::NumericLimits<half_t>::Min())),
abs_tol);
// convert maximal f8_t to fp16 and check if equal to 240.0
ASSERT_NEAR(half_t{240.0}, type_convert<half_t>(f8_convert_sr<f8_t>(half_t{240.0})), abs_tol);
// convert maximal fp16 to fp8 and back, check if clipped to 240.0
ASSERT_NEAR(half_t{240.0},
type_convert<half_t>(f8_convert_sr<f8_t>(ck::NumericLimits<half_t>::Max())),
abs_tol);
// convert QuietNaN fp16 to f8_t and check if it is QuietNaN
ASSERT_NEAR(0x80, f8_convert_sr<f8_t>(ck::NumericLimits<half_t>::QuietNaN()), abs_tol);
// positive fp16 value to fp8 and back, check if holds
half_t pos_half = half_t{0.0078125};
ASSERT_NEAR(pos_half, type_convert<half_t>(f8_convert_sr<f8_t>(pos_half)), abs_tol);
// negative fp16 value to fp8 and back, check if holds
half_t neg_half = half_t{-0.0156250};
ASSERT_NEAR(neg_half, type_convert<half_t>(f8_convert_sr<f8_t>(neg_half)), abs_tol);
}