pytorch/caffe2/utils/threadpool/pthreadpool.h

// pthreadpool header from https://github.com/Maratyszcza/pthreadpool
// for NNPACK
#ifndef CAFFE2_UTILS_PTHREADPOOL_H_
#define CAFFE2_UTILS_PTHREADPOOL_H_

#include "ThreadPoolCommon.h"

#include <stddef.h> // for size_t
#include <stdint.h> // for uint32_t

#if defined(USE_PTHREADPOOL)
// This is a hack.
// Mainly introduced here because
// 1. NNPACK can be compiled to use internal legacy threadpool implementation because much of C2 depends on that.
// 2. Then if we want to use NNPACK in PyTorch, which uses new pthreadpool, then we will supply new pthreadpool pointer
//    to NNPACK. This will not work if NNPACK is compiled with internal legacy threadpool. Thus this guard
//    along with changes in pthreadpool_impl.cc allows us to override that behavior.
//    It enables us to use NNPACK from pytorch using `caffe2::pthreadpool_()`
namespace caffe2 {
class WithCastToNewThreadPool {
  public:
    explicit WithCastToNewThreadPool(bool use_new_threadpool);
    ~WithCastToNewThreadPool();
  private:
    bool use_new_threadpool_;
};
}
#endif

typedef struct pthreadpool* legacy_pthreadpool_t;

typedef void (*legacy_pthreadpool_function_1d_t)(void*, size_t);
typedef void (*legacy_pthreadpool_function_1d_tiled_t)(void*, size_t, size_t);
typedef void (*legacy_pthreadpool_function_2d_t)(void*, size_t, size_t);
typedef void (*legacy_pthreadpool_function_2d_tiled_t)(void*, size_t, size_t, size_t, size_t);
typedef void (*legacy_pthreadpool_function_3d_tiled_t)(
    void*,
    size_t,
    size_t,
    size_t,
    size_t,
    size_t,
    size_t);
typedef void (*legacy_pthreadpool_function_4d_tiled_t)(
    void*,
    size_t,
    size_t,
    size_t,
    size_t,
    size_t,
    size_t,
    size_t,
    size_t);

#ifdef __cplusplus
extern "C" {
#endif

/**
 * Creates a thread pool with the specified number of threads.
 *
 * @param[in]  threads_count  The number of threads in the thread pool.
 *    A value of 0 has special interpretation: it creates a thread for each
 *    processor core available in the system.
 *
 * @returns  A pointer to an opaque thread pool object.
 *    On error the function returns NULL and sets errno accordingly.
 */

// Returns internal threadpool impl.
legacy_pthreadpool_t legacy_pthreadpool_create(size_t threads_count);

/**
 * Queries the number of threads in a thread pool.
 *
 * @param[in]  threadpool  The thread pool to query.
 *
 * @returns  The number of threads in the thread pool.
 */
size_t legacy_pthreadpool_get_threads_count(legacy_pthreadpool_t threadpool);

/**
 * Processes items in parallel using threads from a thread pool.
 *
 * When the call returns, all items have been processed and the thread pool is
 * ready for a new task.
 *
 * @note If multiple threads call this function with the same thread pool, the
 *    calls are serialized.
 *
 * @param[in]  threadpool  The thread pool to use for parallelisation.
 * @param[in]  function    The function to call for each item.
 * @param[in]  argument    The first argument passed to the @a function.
 * @param[in]  items       The number of items to process. The @a function
 *    will be called once for each item.
 */
void legacy_pthreadpool_compute_1d(
    legacy_pthreadpool_t threadpool,
    legacy_pthreadpool_function_1d_t function,
    void* argument,
    size_t range);

void legacy_pthreadpool_parallelize_1d(
    legacy_pthreadpool_t threadpool,
    legacy_pthreadpool_function_1d_t function,
    void* argument,
    size_t range,
    uint32_t flags);

void legacy_pthreadpool_compute_1d_tiled(
    legacy_pthreadpool_t threadpool,
    legacy_pthreadpool_function_1d_tiled_t function,
    void* argument,
    size_t range,
    size_t tile);

void legacy_pthreadpool_compute_2d(
    legacy_pthreadpool_t threadpool,
    legacy_pthreadpool_function_2d_t function,
    void* argument,
    size_t range_i,
    size_t range_j);

void legacy_pthreadpool_compute_2d_tiled(
    legacy_pthreadpool_t threadpool,
    legacy_pthreadpool_function_2d_tiled_t function,
    void* argument,
    size_t range_i,
    size_t range_j,
    size_t tile_i,
    size_t tile_j);

void legacy_pthreadpool_compute_3d_tiled(
    legacy_pthreadpool_t threadpool,
    legacy_pthreadpool_function_3d_tiled_t function,
    void* argument,
    size_t range_i,
    size_t range_j,
    size_t range_k,
    size_t tile_i,
    size_t tile_j,
    size_t tile_k);

void legacy_pthreadpool_compute_4d_tiled(
    legacy_pthreadpool_t threadpool,
    legacy_pthreadpool_function_4d_tiled_t function,
    void* argument,
    size_t range_i,
    size_t range_j,
    size_t range_k,
    size_t range_l,
    size_t tile_i,
    size_t tile_j,
    size_t tile_k,
    size_t tile_l);

/**
 * Terminates threads in the thread pool and releases associated resources.
 *
 * @warning  Accessing the thread pool after a call to this function constitutes
 *    undefined behaviour and may cause data corruption.
 *
 * @param[in,out]  threadpool  The thread pool to destroy.
 */
void legacy_pthreadpool_destroy(legacy_pthreadpool_t threadpool);

#ifdef USE_INTERNAL_PTHREADPOOL_IMPL

#define pthreadpool_t legacy_pthreadpool_t
#define pthreadpool_function_1d_t legacy_pthreadpool_function_1d_t
#define pthreadpool_function_1d_tiled_t legacy_pthreadpool_function_1d_tiled_t
#define pthreadpool_function_2d_t legacy_pthreadpool_function_2d_t
#define pthreadpool_function_2d_tiled_t legacy_pthreadpool_function_2d_tiled_t
#define pthreadpool_function_3d_tiled_t legacy_pthreadpool_function_3d_tiled_t
#define pthreadpool_function_4d_tiled_t legacy_pthreadpool_function_4d_tiled_t
#define pthreadpool_create legacy_pthreadpool_create
#define pthreadpool_destroy legacy_pthreadpool_destroy
#define pthreadpool_get_threads_count legacy_pthreadpool_get_threads_count
#define pthreadpool_compute_1d legacy_pthreadpool_compute_1d
#define pthreadpool_parallelize_1d legacy_pthreadpool_parallelize_1d
#define pthreadpool_compute_1d_tiled legacy_pthreadpool_compute_1d_tiled
#define pthreadpool_compute_2d legacy_pthreadpool_compute_2d
#define pthreadpool_compute_2d_tiled legacy_pthreadpool_compute_2d_tiled
#define pthreadpool_compute_3d_tiled legacy_pthreadpool_compute_3d_tiled
#define pthreadpool_compute_4d_tiled legacy_pthreadpool_compute_4d_tiled

#endif /* USE_INTERNAL_PTHREADPOOL_IMPL */

#ifdef __cplusplus
} /* extern "C" */
#endif

#endif // CAFFE2_UTILS_PTHREADPOOL_H_