kernels/fmha_utils.h

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#pragma once

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <cuda_runtime_api.h>
#include <cuda_fp16.h>
#include <cuda_bf16.h>

////////////////////////////////////////////////////////////////////////////////////////////////////

#define FMHA_CHECK_CUDA( call )                                                                    \
    do {                                                                                           \
        cudaError_t status_ = call;                                                                \
        if( status_ != cudaSuccess ) {                                                             \
            fprintf( stderr,                                                                       \
                     "CUDA error (%s:%d): %s\n",                                                   \
                     __FILE__,                                                                     \
                     __LINE__,                                                                     \
                     cudaGetErrorString( status_ ) );                                              \
            exit( 1 );                                                                             \
        }                                                                                          \
    } while( 0 )

////////////////////////////////////////////////////////////////////////////////////////////////////

enum Data_type { DATA_TYPE_FP16, DATA_TYPE_BF16, DATA_TYPE_FP32, DATA_TYPE_INT32, DATA_TYPE_INT8 };

////////////////////////////////////////////////////////////////////////////////////////////////////

static inline void set_alpha( uint32_t &alpha, float norm, Data_type dtype ) {
    if( dtype == DATA_TYPE_FP16 ) {
        half x = __float2half_rn( norm );
        uint16_t h = reinterpret_cast<const uint16_t &>( x );
        ushort2 h2 = { h, h };
        alpha = reinterpret_cast<const uint32_t &>( h2 );
    } else if( dtype == DATA_TYPE_BF16 ) {
        __nv_bfloat16 x = __float2bfloat16( norm );
        uint16_t h = reinterpret_cast<const uint16_t &>( x );
        ushort2 h2 = { h, h };
        alpha = reinterpret_cast<const uint32_t &>( h2 );
    } else if( dtype == DATA_TYPE_FP32 ) {
        alpha = reinterpret_cast<const uint32_t &>( norm );
    } else if( dtype == DATA_TYPE_INT32 ) {
        int32_t inorm = static_cast<int32_t>( norm );
        alpha = reinterpret_cast<const uint32_t &>( inorm );
    } else {
        assert( false );
    }
}

////////////////////////////////////////////////////////////////////////////////////////////////////

static inline size_t get_size_in_bytes( size_t n, Data_type dtype ) {
    switch( dtype ) {
    case DATA_TYPE_FP32:
        return n * 4;
    case DATA_TYPE_FP16:
        return n * 2;
    case DATA_TYPE_BF16:
        return n * 2;
    case DATA_TYPE_INT32:
        return n * 4;
    case DATA_TYPE_INT8:
        return n;
    default:
        assert( false );
        return 0;
    }
}

////////////////////////////////////////////////////////////////////////////////////////////////////