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Fix PR30890: Reduction across teams hangs 

__kmpc_reduce_nowait() correctly swapped the teams for reductions
in a teams construct. Apply the same logic to __kmpc_reduce() and
__kmpc_reduce_end().

Differential Revision: https://reviews.llvm.org/D40753

llvm-svn: 319788
This commit is contained in:
Jonas Hahnfeld 2017-12-05 16:51:24 +00:00
parent 7e7566323d
commit a4ca525c1b
2 changed files with 133 additions and 23 deletions
openmp/runtime
src
kmp_csupport.cpp
test/misc_bugs
teams-reduction.c

93
openmp/runtime/src/kmp_csupport.cpp
View File

@ -3202,6 +3202,43 @@ __kmp_end_critical_section_reduce_block(ident_t *loc, kmp_int32 global_tid,
#endif // KMP_USE_DYNAMIC_LOCK
} // __kmp_end_critical_section_reduce_block
#if OMP_40_ENABLED
static __forceinline int
__kmp_swap_teams_for_teams_reduction(kmp_info_t *th, kmp_team_t **team_p,
int *task_state) {
kmp_team_t *team;
// Check if we are inside the teams construct?
if (th->th.th_teams_microtask) {
*team_p = team = th->th.th_team;
if (team->t.t_level == th->th.th_teams_level) {
// This is reduction at teams construct.
KMP_DEBUG_ASSERT(!th->th.th_info.ds.ds_tid); // AC: check that tid == 0
// Let's swap teams temporarily for the reduction.
th->th.th_info.ds.ds_tid = team->t.t_master_tid;
th->th.th_team = team->t.t_parent;
th->th.th_team_nproc = th->th.th_team->t.t_nproc;
th->th.th_task_team = th->th.th_team->t.t_task_team[0];
*task_state = th->th.th_task_state;
th->th.th_task_state = 0;
return 1;
}
}
return 0;
}
static __forceinline void
__kmp_restore_swapped_teams(kmp_info_t *th, kmp_team_t *team, int task_state) {
// Restore thread structure swapped in __kmp_swap_teams_for_teams_reduction.
th->th.th_info.ds.ds_tid = 0;
th->th.th_team = team;
th->th.th_team_nproc = team->t.t_nproc;
th->th.th_task_team = team->t.t_task_team[task_state];
th->th.th_task_state = task_state;
}
#endif
/* 2.a.i. Reduce Block without a terminating barrier */
/*!
@ingroup SYNCHRONIZATION
@ -3228,8 +3265,8 @@ __kmpc_reduce_nowait(ident_t *loc, kmp_int32 global_tid, kmp_int32 num_vars,
int retval = 0;
PACKED_REDUCTION_METHOD_T packed_reduction_method;
#if OMP_40_ENABLED
kmp_team_t *team;
kmp_info_t *th;
kmp_team_t *team;
int teams_swapped = 0, task_state;
#endif
KA_TRACE(10, ("__kmpc_reduce_nowait() enter: called T#%d\n", global_tid));
@ -3254,22 +3291,7 @@ __kmpc_reduce_nowait(ident_t *loc, kmp_int32 global_tid, kmp_int32 num_vars,
#if OMP_40_ENABLED
th = __kmp_thread_from_gtid(global_tid);
if (th->th.th_teams_microtask) { // AC: check if we are inside the teams
// construct?
team = th->th.th_team;
if (team->t.t_level == th->th.th_teams_level) {
// this is reduction at teams construct
KMP_DEBUG_ASSERT(!th->th.th_info.ds.ds_tid); // AC: check that tid == 0
// Let's swap teams temporarily for the reduction barrier
teams_swapped = 1;
th->th.th_info.ds.ds_tid = team->t.t_master_tid;
th->th.th_team = team->t.t_parent;
th->th.th_team_nproc = th->th.th_team->t.t_nproc;
th->th.th_task_team = th->th.th_team->t.t_task_team[0];
task_state = th->th.th_task_state;
th->th.th_task_state = 0;
}
}
teams_swapped = __kmp_swap_teams_for_teams_reduction(th, &team, &task_state);
#endif // OMP_40_ENABLED
// packed_reduction_method value will be reused by __kmp_end_reduce* function,
@ -3373,12 +3395,7 @@ __kmpc_reduce_nowait(ident_t *loc, kmp_int32 global_tid, kmp_int32 num_vars,
}
#if OMP_40_ENABLED
if (teams_swapped) {
// Restore thread structure
th->th.th_info.ds.ds_tid = 0;
th->th.th_team = team;
th->th.th_team_nproc = team->t.t_nproc;
th->th.th_task_team = team->t.t_task_team[task_state];
th->th.th_task_state = task_state;
__kmp_restore_swapped_teams(th, team, task_state);
}
#endif
KA_TRACE(
@ -3466,6 +3483,11 @@ kmp_int32 __kmpc_reduce(ident_t *loc, kmp_int32 global_tid, kmp_int32 num_vars,
KMP_COUNT_BLOCK(REDUCE_wait);
int retval = 0;
PACKED_REDUCTION_METHOD_T packed_reduction_method;
#if OMP_40_ENABLED
kmp_info_t *th;
kmp_team_t *team;
int teams_swapped = 0, task_state;
#endif
KA_TRACE(10, ("__kmpc_reduce() enter: called T#%d\n", global_tid));
@ -3487,6 +3509,11 @@ kmp_int32 __kmpc_reduce(ident_t *loc, kmp_int32 global_tid, kmp_int32 num_vars,
__kmp_push_sync(global_tid, ct_reduce, loc, NULL);
#endif
#if OMP_40_ENABLED
th = __kmp_thread_from_gtid(global_tid);
teams_swapped = __kmp_swap_teams_for_teams_reduction(th, &team, &task_state);
#endif // OMP_40_ENABLED
packed_reduction_method = __kmp_determine_reduction_method(
loc, global_tid, num_vars, reduce_size, reduce_data, reduce_func, lck);
__KMP_SET_REDUCTION_METHOD(global_tid, packed_reduction_method);
@ -3548,6 +3575,11 @@ kmp_int32 __kmpc_reduce(ident_t *loc, kmp_int32 global_tid, kmp_int32 num_vars,
// should never reach this block
KMP_ASSERT(0); // "unexpected method"
}
#if OMP_40_ENABLED
if (teams_swapped) {
__kmp_restore_swapped_teams(th, team, task_state);
}
#endif
KA_TRACE(10,
("__kmpc_reduce() exit: called T#%d: method %08x, returns %08x\n",
@ -3570,9 +3602,19 @@ void __kmpc_end_reduce(ident_t *loc, kmp_int32 global_tid,
kmp_critical_name *lck) {
PACKED_REDUCTION_METHOD_T packed_reduction_method;
#if OMP_40_ENABLED
kmp_info_t *th;
kmp_team_t *team;
int teams_swapped = 0, task_state;
#endif
KA_TRACE(10, ("__kmpc_end_reduce() enter: called T#%d\n", global_tid));
#if OMP_40_ENABLED
th = __kmp_thread_from_gtid(global_tid);
teams_swapped = __kmp_swap_teams_for_teams_reduction(th, &team, &task_state);
#endif // OMP_40_ENABLED
packed_reduction_method = __KMP_GET_REDUCTION_METHOD(global_tid);
// this barrier should be visible to a customer and to the threading profile
@ -3660,6 +3702,11 @@ void __kmpc_end_reduce(ident_t *loc, kmp_int32 global_tid,
// should never reach this block
KMP_ASSERT(0); // "unexpected method"
}
#if OMP_40_ENABLED
if (teams_swapped) {
__kmp_restore_swapped_teams(th, team, task_state);
}
#endif
if (__kmp_env_consistency_check)
__kmp_pop_sync(global_tid, ct_reduce, loc);

63
openmp/runtime/test/misc_bugs/teams-reduction.c Normal file
View File

@ -0,0 +1,63 @@
// RUN: %libomp-compile-and-run
//
// The test checks the teams construct with reduction executed on the host.
//
#include <stdio.h>
#include <omp.h>
#include <stdint.h>
#ifndef N_TEAMS
#define N_TEAMS 4
#endif
#ifndef N_THR
#define N_THR 3
#endif
// Internal library stuff to emulate compiler's code generation:
#ifdef __cplusplus
extern "C" {
#endif
typedef struct {
int32_t reserved_1;
int32_t flags;
int32_t reserved_2;
int32_t reserved_3;
char const *psource;
} ident_t;
static ident_t dummy_loc = {0, 2, 0, 0, ";dummyFile;dummyFunc;0;0;;"};
typedef int32_t kmp_critical_name[8];
kmp_critical_name crit;
int32_t __kmpc_global_thread_num(ident_t *);
void __kmpc_push_num_teams(ident_t *, int32_t global_tid, int32_t num_teams,
int32_t num_threads);
void __kmpc_fork_teams(ident_t *, int32_t argc, void *microtask, ...);
int32_t __kmpc_reduce(ident_t *, int32_t global_tid, int32_t num_vars,
size_t reduce_size, void *reduce_data, void *reduce_func,
kmp_critical_name *lck);
void __kmpc_end_reduce(ident_t *, int32_t global_tid, kmp_critical_name *lck);
#ifdef __cplusplus
}
#endif
// Outlined entry point:
void outlined(int32_t *gtid, int32_t *tid) {
int32_t ret = __kmpc_reduce(&dummy_loc, *gtid, 0, 0, NULL, NULL, &crit);
__kmpc_end_reduce(&dummy_loc, *gtid, &crit);
}
int main() {
int32_t th = __kmpc_global_thread_num(NULL); // registers initial thread
__kmpc_push_num_teams(&dummy_loc, th, N_TEAMS, N_THR);
__kmpc_fork_teams(&dummy_loc, 0, &outlined);
// Test did not hang -> passed!
printf("passed\n");
return 0;
}