block_raking_layout.cuh

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 * Copyright (c) 2011, Duane Merrill.  All rights reserved.
 * Copyright (c) 2011-2018, NVIDIA CORPORATION.  All rights reserved.
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#pragma once
 
#include "../util_macro.cuh"
#include "../util_arch.cuh"
#include "../util_type.cuh"
#include "../util_namespace.cuh"
 
CUB_NS_PREFIX
 
namespace cub {
 
template <
    typename    T,
    int         BLOCK_THREADS,
    int         PTX_ARCH = CUB_PTX_ARCH>
struct BlockRakingLayout
{
    //---------------------------------------------------------------------
    // Constants and type definitions
    //---------------------------------------------------------------------
 
    enum
    {
        SHARED_ELEMENTS = BLOCK_THREADS,
 
        MAX_RAKING_THREADS = CUB_MIN(BLOCK_THREADS, CUB_WARP_THREADS(PTX_ARCH)),
 
        SEGMENT_LENGTH = (SHARED_ELEMENTS + MAX_RAKING_THREADS - 1) / MAX_RAKING_THREADS,
 
        RAKING_THREADS = (SHARED_ELEMENTS + SEGMENT_LENGTH - 1) / SEGMENT_LENGTH,
 
        HAS_CONFLICTS = (CUB_SMEM_BANKS(PTX_ARCH) % SEGMENT_LENGTH == 0),
 
        CONFLICT_DEGREE = (HAS_CONFLICTS) ?
            (MAX_RAKING_THREADS * SEGMENT_LENGTH) / CUB_SMEM_BANKS(PTX_ARCH) :
            1,
 
        USE_SEGMENT_PADDING = ((SEGMENT_LENGTH & 1) == 0) && (SEGMENT_LENGTH > 2),
 
        GRID_ELEMENTS = RAKING_THREADS * (SEGMENT_LENGTH + USE_SEGMENT_PADDING),
 
        UNGUARDED = (SHARED_ELEMENTS % RAKING_THREADS == 0),
    };
 
 
    struct __align__(16) _TempStorage
    {
        T buff[BlockRakingLayout::GRID_ELEMENTS];
    };
 
    struct TempStorage : Uninitialized<_TempStorage> {};
 
 
    static __device__ __forceinline__ T* PlacementPtr(
        TempStorage &temp_storage,
        unsigned int linear_tid)
    {
        // Offset for partial
        unsigned int offset = linear_tid;
 
        // Add in one padding element for every segment
        if (USE_SEGMENT_PADDING > 0)
        {
            offset += offset / SEGMENT_LENGTH;
        }
 
        // Incorporating a block of padding partials every shared memory segment
        return temp_storage.Alias().buff + offset;
    }
 
 
    static __device__ __forceinline__ T* RakingPtr(
        TempStorage &temp_storage,
        unsigned int linear_tid)
    {
        return temp_storage.Alias().buff + (linear_tid * (SEGMENT_LENGTH + USE_SEGMENT_PADDING));
    }
};
 
}               // CUB namespace
CUB_NS_POSTFIX  // Optional outer namespace(s)