libxomp.h

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/*  
 * A common layer for both gomp and omni runtime library
 *  Liao 1/20/2009
 *  */
#ifndef LIB_XOMP_H 
#define LIB_XOMP_H

// Fortran outlined function uses one parameter for each variable to be passed by reference
// We predefine a max number of parameters to be allowed here.
#define MAX_OUTLINED_FUNC_PARAMETER_COUNT 256
#ifdef __cplusplus
extern "C" {
#endif

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h> // for abort()
#include <assert.h>
#include <sys/time.h>

// return the current time stamp in a double floating point number
extern double xomp_time_stamp(void);
extern int env_region_instr_val; // save the environment variable value for instrumentation support
//e.g. export XOMP_REGION_INSTR=0|1

//enum omp_rtl_enum {
//  e_gomp,
//  e_omni,
//  e_last_rtl
//};
//
//extern omp_rtl_enum rtl_type;

//Runtime library initialization routine
extern void XOMP_init (int argc, char ** argv);
extern void xomp_init (void);

// Runtime library termination routine
extern void XOMP_terminate (int exitcode);

// func: pointer to a function which will be run in parallel
// data: pointer to a data segment which will be used as the arguments of func
// ifClauseValue: set to if-clause-expression if if-clause exists, or default is 1. 
// numThreadsSpecified: set to the expression of num_threads clause if the clause exists, or default is 0
// file_name:line_no the start source file info about this parallel region, used to pass source level info. to runtime
extern void XOMP_parallel_start (void (*func) (void *), void *data, unsigned ifClauseValue, unsigned numThreadsSpecified, char* file_name, int line_no);
extern void XOMP_parallel_end (char* file_name, int line_no);

/* Initialize sections and return the next section id (starting from 0) to be executed by the current thread */
extern int XOMP_sections_init_next(int section_count); 

/* Return the next section id (starting from 0) to be executed by the current thread. Return value <0 means no sections left */
extern int XOMP_sections_next(void); 

/* Called after the current thread is told that all sections are executed. It synchronizes all threads also. */
extern void XOMP_sections_end(void);

/* Called after the current thread is told that all sections are executed. It does not synchronizes all threads. */
extern void XOMP_sections_end_nowait(void);

extern void XOMP_task (void (*) (void *), void *, void (*) (void *, void *),
                       long, long, bool, unsigned);
extern void XOMP_taskwait (void);

// scheduler functions, union of runtime library functions
// empty body if not used by one
// scheduler initialization, only meaningful used for OMNI

// Default loop scheduling, worksharing without any schedule clause, upper bounds are inclusive
// Kick in before all runtime libraries. We use the default loop scheduling from XOMP regardless the runtime chosen.
extern void XOMP_loop_default(int lower, int upper, int stride, long* n_lower, long* n_upper);

// Non-op for gomp
extern void XOMP_loop_static_init(int lower, int upper, int stride, int chunk_size);
extern void XOMP_loop_dynamic_init(int lower, int upper, int stride, int chunk_size);
extern void XOMP_loop_guided_init(int lower, int upper, int stride, int chunk_size);
extern void XOMP_loop_runtime_init(int lower, int upper, int stride);

//  ordered case
extern void XOMP_loop_ordered_static_init(int lower, int upper, int stride, int chunk_size);
extern void XOMP_loop_ordered_dynamic_init(int lower, int upper, int stride, int chunk_size);
extern void XOMP_loop_ordered_guided_init(int lower, int upper, int stride, int chunk_size);
extern void XOMP_loop_ordered_runtime_init(int lower, int upper, int stride);


// if (start), 
// mostly used because of gomp, omni will just call  XOMP_loop_xxx_next();
// (long start, long end, long incr, long chunk_size,long *istart, long *iend)
//  upper bounds are non-inclusive, 
//  bounds for inclusive loop control will need +/-1 , depending on incremental/decremental cases
extern bool XOMP_loop_static_start (long, long, long, long, long *, long *);
extern bool XOMP_loop_dynamic_start (long, long, long, long, long *, long *);
extern bool XOMP_loop_guided_start (long, long, long, long, long *, long *);
extern bool XOMP_loop_runtime_start (long, long, long, long *, long *);

extern bool XOMP_loop_ordered_static_start (long, long, long, long, long *, long *);
extern bool XOMP_loop_ordered_dynamic_start (long, long, long, long, long *, long *);
extern bool XOMP_loop_ordered_guided_start (long, long, long, long, long *, long *);
extern bool XOMP_loop_ordered_runtime_start (long, long, long, long *, long *);

// next
extern bool XOMP_loop_static_next (long *, long *);
extern bool XOMP_loop_dynamic_next (long *, long *);
extern bool XOMP_loop_guided_next (long *, long *);
extern bool XOMP_loop_runtime_next (long *, long *);

extern bool XOMP_loop_ordered_static_next (long *, long *);
extern bool XOMP_loop_ordered_dynamic_next (long *, long *);
extern bool XOMP_loop_ordered_guided_next (long *, long *);
extern bool XOMP_loop_ordered_runtime_next (long *, long *);

//--------------end of  loop functions 

extern void XOMP_barrier (void);
extern void XOMP_critical_start (void** data); 
extern void XOMP_critical_end (void** data);
extern bool XOMP_single(void);
extern bool XOMP_master(void);

extern void XOMP_atomic_start (void);
extern void XOMP_atomic_end (void);

extern void XOMP_loop_end (void);
extern void XOMP_loop_end_nowait (void);
   // --- end loop functions ---
// flush without variable list
extern void XOMP_flush_all (void);
// omp flush with variable list, flush one by one, given each's start address and size
extern void XOMP_flush_one (char * startAddress, int nbyte);


// omp ordered directive
extern void XOMP_ordered_start (void);
extern void XOMP_ordered_end (void);

//--------------------- extensions to support OpenMP accelerator model experimental implementation------
// We only include 
//--------------------- kernel launch ------------------

// the max number of threads per thread block of the first available device
extern size_t xomp_get_maxThreadsPerBlock();

//get the max number of 1D blocks for a given input length
extern size_t xomp_get_max1DBlock(size_t ss);

// Get the max number threads for one dimension (x or y) of a 2D block
// Two factors are considered: the total number of threads within the 2D block must<= total threads per block
//  x * y <= maxThreadsPerBlock 512 or 1024
// each dimension: the number of threads must <= maximum x/y-dimension
//    x <= maxThreadsDim[0],  1024
//    y <= maxThreadsDim[1], 1024 
//  maxThreadsDim[0] happens to be equal to  maxThreadsDim[1] so we use a single function to calculate max segments for both dimensions
extern size_t xomp_get_max_threads_per_dimesion_2D ();

// return the max number of segments for a dimension (either x or y) of a 2D block
extern size_t xomp_get_maxSegmentsPerDimensionOf2DBlock(size_t dimension_size);

//------------------memory allocation/copy/free----------------------------------
//Allocate device memory and return the pointer
// This should be a better interface than cudaMalloc()
// since it mimics malloc() closely
/*
return a pointer to the allocated space 
   * upon successful completion with size not equal to 0
return a null pointer if
  * size is 0 
  * failure due to any reason
*/
extern void* xomp_deviceMalloc(size_t size);

// A host version
extern void* xomp_hostMalloc(size_t size);

//get the time stamp for now, up to microsecond resolution: 1e-6 , but maybe 1e-4 in practice
extern double xomp_time_stamp();


// memory copy from src to dest, return the pointer to dest. NULL pointer if anything is wrong 
extern void * xomp_memcpyHostToDevice (void *dest, const void * src, size_t n_n);
extern void * xomp_memcpyDeviceToHost (void *dest, const void * src, size_t n_n);
// copy a dynamically allocated host source array to linear dest address on a GPU device. the dimension information of the source array
// is given by: int dimensions[dimension_size], with known element size. 
// bytes_copied reports the total bytes copied by this function.  
// Note: It cannot be used copy static arrays declared like type array[N][M] !!
extern void * xomp_memcpyDynamicHostToDevice (void *dest, const void * src, int * dimensions, size_t dimension_size, size_t element_size, size_t *bytes_copied);

// copy linear src memory to dynamically allocated destination, with dimension information given by
// int dimensions[dimension_size]
// the source memory has total n continuous memory, with known size for each element
// the total bytes copied by this function is reported by bytes_copied
extern void * xomp_memcpyDynamicDeviceToHost (void *dest, int * dimensions, size_t dimension_size, const void * src, size_t element_size, size_t *bytes_copied);

extern void * xomp_memcpyDeviceToDevice (void *dest, const void * src, size_t n_n);
extern void * xomp_memcpyHostToHost (void *dest, const void * src, size_t n_n); // same as memcpy??


// free the device memory pointed by a pointer, return false in case of failure, otherwise return true
extern bool xomp_freeDevice(void* devPtr);
// free the host memory pointed by a pointer, return false in case of failure, otherwise return true
extern bool xomp_freeHost(void* hostPtr);

/* Allocation/Free functions for Host */
/* Allocate a multi-dimensional array
 *
 * Input parameters:
 *  int *dimensions:  an integer array storing the size of each dimension
 *  size_t dimension_num: the number of dimensions
 *  size_t esize: the size of an array element
 *
 * return:
 *  the pointer to the allocated array
 * */
extern void * xomp_mallocArray(int * dimensions, size_t dimension_num, size_t esize);

extern void xomp_freeArrayPointer (void* array, int * dimensions, size_t dimension_num);


/* CUDA reduction support */
//------------ types for CUDA reduction support---------
// Reduction for regular OpenMP is supported by compiler translation. No runtime support is needed.
// For the accelerator model experimental implementation, we use a two-level reduction method:
// thread-block level within GPU + beyond-block level on CPU

/* an internal union type to be flexible for all types associated with reduction operations 
   We don't really want to expose this to the compiler to simplify the compiler translation.
*/
// We try to limit the numbers of runtime data types exposed to a compiler.
// A set of integers to represent reduction operations
#define XOMP_REDUCTION_PLUS 6
#define XOMP_REDUCTION_MINUS 7
#define XOMP_REDUCTION_MUL 8
#define XOMP_REDUCTION_BITAND 9 // &
#define XOMP_REDUCTION_BITOR 10 // |
#define XOMP_REDUCTION_BITXOR  11 // ^
#define XOMP_REDUCTION_LOGAND 12 // &&
#define XOMP_REDUCTION_LOGOR 13  // ||

#if 0
// No linker support for device code. We have to put implementation of these device functions into the header
// TODO: wait until nvcc supports linker for device code.
//#define XOMP_INNER_BLOCK_REDUCTION_DECL(dtype) \
//__device__ void xomp_inner_block_reduction_##dtype(dtype local_value, dtype * grid_level_results, int reduction_op);
//
//XOMP_INNER_BLOCK_REDUCTION_DECL(int)
//XOMP_INNER_BLOCK_REDUCTION_DECL(float)
//XOMP_INNER_BLOCK_REDUCTION_DECL(double)
//
//#undef XOMP_INNER_BLOCK_REDUCTION_DECL

#endif

#define XOMP_BEYOND_BLOCK_REDUCTION_DECL(dtype) \
  dtype xomp_beyond_block_reduction_##dtype(dtype * per_block_results, int numBlocks, int reduction_op);

XOMP_BEYOND_BLOCK_REDUCTION_DECL(int)
XOMP_BEYOND_BLOCK_REDUCTION_DECL(float)
XOMP_BEYOND_BLOCK_REDUCTION_DECL(double)

#undef XOMP_BEYOND_BLOCK_REDUCTION_DECL
// Liao, 8/29/2013
// Support round-robin static scheduling of loop iterations running on GPUs (accelerator)
// Static even scheduling may cause each thread to touch too much data, which stress memory channel.
// NOT IN USE. We use compiler to generate the variables instead of using a runtime data structure.
struct XOMP_accelerator_thread {
    int num;            /* the thread number of this thread in team */
    int num_thds;       /* current running thread, referenced by children */
    int in_parallel;    /* current thread executes the region in parallel */

    /* used for schedule */
    int loop_chunk_size;  //*************  this is the chunk size
    int loop_end;         //*************  equivalent to upper limit, up
    int loop_sched_index; //*************  lb+chunk_size*tp->num  (num is the thread number of this thread in team)
    int loop_stride;      //*************   chunk_size * nthds     /* used for static scheduling */

    /* for 'lastprivate' */
    int is_last;  
};

#define XOMP_MAX_MAPPED_VARS 256 // for simplicity, we use preallocated memory for storing the mapped variable list
/* Test runtime support for nested device data environments */
/* Liao, May 2, 2013*/
/* A data structure to keep track of a mapped variable
 *  Right now we use memory address of the original variable and the size of the variable
 * */
struct XOMP_mapped_variable
{
  void * address; // original variable's address
  int size; 
  void * dev_address; // the corresponding device variable's address
  bool copyBack; // if this variable should be copied back to HOST
};

extern void copy_mapped_variable (struct XOMP_mapped_variable* desc, struct XOMP_mapped_variable* src );

/* A doubly linked list for tracking Device Data Environment (DDE) */
struct DDE_data {
    // Do we need this at all?  we can allocate/deallocate data without saving region ID
 int Region_ID;  // hash of the AST node? or just memory address of the AST node for now 

// array of the newly mapped variables
 int new_variable_count;
 struct XOMP_mapped_variable* new_variables;
 //struct XOMP_mapped_variable new_variables[XOMP_MAX_MAPPED_VARS];

// array of inherited mapped variable from possible upper level DDEs
 int inherited_variable_count;
 struct XOMP_mapped_variable*  inherited_variables;
 //struct XOMP_mapped_variable  inherited_variables[XOMP_MAX_MAPPED_VARS];

 // link to its parent node
 struct  DDE_data* parent;
 // link to its child node
 struct  DDE_data* child;
};

// The head of the list of DDE data nodes
extern struct DDE_data* DDE_head; //TODO. We don't really need this head pointer, it is like a stack, access the end is enough
// The tail of the list
extern struct DDE_data* DDE_tail;

// create a new DDE-data node and append it to the end of the tracking list
// copy all variables from its parent node to be into the set of inherited variable set.
//void XOMP_Device_Data_Environment_Enter();
extern void xomp_deviceDataEnvironmentEnter();

// Check if an original  variable is already mapped in enclosing data environment, return its device variable's address if yes.
// return NULL if not
//void* XOMP_Device_Data_Environment_Get_Inherited_Variable (void* original_variable_address, int size);
extern void* xomp_deviceDataEnvironmentGetInheritedVariable (void* original_variable_address, int size);

//void XOMP_Device_Data_Environment_Add_Variable (void* var_addr, int var_size, void * dev_addr);
extern void xomp_deviceDataEnvironmentAddVariable (void* var_addr, int var_size, void * dev_addr, bool copy_back);

// Exit current DDE: deallocate device memory, delete the DDE-data node from the end of the tracking list
//void XOMP_Device_Data_Environment_Exit();   
extern void xomp_deviceDataEnvironmentExit();   


#ifdef __cplusplus
 }
#endif
 
#endif /* LIB_XOMP_H */