Files
clang-p2996/openmp/runtime/test/tasking/kmp_taskloop.c
Jonathan Peyton 93e17cfe6c Add recursive task scheduling strategy to taskloop implementation
Summary:
Taskloop implementation is extended by using recursive task scheduling.
Envirable KMP_TASKLOOP_MIN_TASKS added as a manual threshold for the user
to switch from recursive to linear tasks scheduling.

Details:
* The calculations for the loop parameters are moved from __kmp_taskloop_linear
  upper level
* Initial calculation is done in the __kmpc_taskloop, further range splitting
  is done in the __kmp_taskloop_recur.
* Added threshold to switch from recursive to linear tasks scheduling;
* One half of split range is scheduled as an internal task which just moves
  sub-range parameters to the stealing thread that continues recursive
  scheduling (if number of tasks still enough), the other half is processed
  recursively;
* Internal task duplication routine fixed to assign parent task, that was not
  needed when all tasks were scheduled by same thread, but is needed now.

Patch by Andrey Churbanov

Differential Revision: https://reviews.llvm.org/D35273

llvm-svn: 308338
2017-07-18 18:50:13 +00:00

160 lines
4.1 KiB
C

// RUN: %libomp-compile-and-run
// RUN: %libomp-compile && env KMP_TASKLOOP_MIN_TASKS=1 %libomp-run
#include <stdio.h>
#include <omp.h>
#include "omp_my_sleep.h"
#define N 4
#define GRAIN 10
#define STRIDE 3
// globals
int th_counter[N];
int counter;
// Compiler-generated code (emulation)
typedef struct ident {
void* dummy;
} ident_t;
typedef struct shar {
int(*pth_counter)[N];
int *pcounter;
int *pj;
} *pshareds;
typedef struct task {
pshareds shareds;
int(* routine)(int,struct task*);
int part_id;
// privates:
unsigned long long lb; // library always uses ULONG
unsigned long long ub;
int st;
int last;
int i;
int j;
int th;
} *ptask, kmp_task_t;
typedef int(* task_entry_t)( int, ptask );
void
__task_dup_entry(ptask task_dst, ptask task_src, int lastpriv)
{
// setup lastprivate flag
task_dst->last = lastpriv;
// could be constructor calls here...
}
// OpenMP RTL interfaces
typedef unsigned long long kmp_uint64;
typedef long long kmp_int64;
#ifdef __cplusplus
extern "C" {
#endif
void
__kmpc_taskloop(ident_t *loc, int gtid, kmp_task_t *task, int if_val,
kmp_uint64 *lb, kmp_uint64 *ub, kmp_int64 st,
int nogroup, int sched, kmp_int64 grainsize, void *task_dup );
ptask
__kmpc_omp_task_alloc( ident_t *loc, int gtid, int flags,
size_t sizeof_kmp_task_t, size_t sizeof_shareds,
task_entry_t task_entry );
void __kmpc_atomic_fixed4_add(void *id_ref, int gtid, int * lhs, int rhs);
int __kmpc_global_thread_num(void *id_ref);
#ifdef __cplusplus
}
#endif
// User's code
int task_entry(int gtid, ptask task)
{
pshareds pshar = task->shareds;
for( task->i = task->lb; task->i <= (int)task->ub; task->i += task->st ) {
task->th = omp_get_thread_num();
__kmpc_atomic_fixed4_add(NULL,gtid,pshar->pcounter,1);
__kmpc_atomic_fixed4_add(NULL,gtid,&((*pshar->pth_counter)[task->th]),1);
task->j = task->i;
}
my_sleep( 0.1 ); // sleep 100 ms in order to allow other threads to steal tasks
if( task->last ) {
*(pshar->pj) = task->j; // lastprivate
}
return 0;
}
int main()
{
int i, j, gtid = __kmpc_global_thread_num(NULL);
ptask task;
pshareds psh;
omp_set_dynamic(0);
counter = 0;
for( i=0; i<N; ++i )
th_counter[i] = 0;
#pragma omp parallel num_threads(N)
{
#pragma omp master
{
int gtid = __kmpc_global_thread_num(NULL);
/*
* This is what the OpenMP runtime calls correspond to:
#pragma omp taskloop num_tasks(N) lastprivate(j)
for( i=0; i<N*GRAIN*STRIDE-1; i+=STRIDE )
{
int th = omp_get_thread_num();
#pragma omp atomic
counter++;
#pragma omp atomic
th_counter[th]++;
j = i;
}
*/
task = __kmpc_omp_task_alloc(NULL,gtid,1,sizeof(struct task),sizeof(struct shar),&task_entry);
psh = task->shareds;
psh->pth_counter = &th_counter;
psh->pcounter = &counter;
psh->pj = &j;
task->lb = 0;
task->ub = N*GRAIN*STRIDE-2;
task->st = STRIDE;
__kmpc_taskloop(
NULL, // location
gtid, // gtid
task, // task structure
1, // if clause value
&task->lb, // lower bound
&task->ub, // upper bound
STRIDE, // loop increment
0, // 1 if nogroup specified
2, // schedule type: 0-none, 1-grainsize, 2-num_tasks
N, // schedule value (ignored for type 0)
(void*)&__task_dup_entry // tasks duplication routine
);
} // end master
} // end parallel
// check results
if( j != N*GRAIN*STRIDE-STRIDE ) {
printf("Error in lastprivate, %d != %d\n",j,N*GRAIN*STRIDE-STRIDE);
return 1;
}
if( counter != N*GRAIN ) {
printf("Error, counter %d != %d\n",counter,N*GRAIN);
return 1;
}
for( i=0; i<N; ++i ) {
if( th_counter[i] % GRAIN ) {
printf("Error, th_counter[%d] = %d\n",i,th_counter[i]);
return 1;
}
}
printf("passed\n");
return 0;
}