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Simplify __kmp_expand_threads 

This change simplifies __kmp_expand_threads to take a single argument.
Previously, it allowed two arguments and had logic to decide on different
potential expansion sizes. However, no calls to __kmp_expand_threads in the
runtime make use of this extra logic. Thus the extra argument and logic is
removed here.

Patch by Terry Wilmarth

Differential Revision: https://reviews.llvm.org/D41836

llvm-svn: 322204
This commit is contained in:
Jonathan Peyton 2018-01-10 18:27:01 +00:00
parent bff8ded906
commit 1800ecec70
1 changed files with 12 additions and 37 deletions
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49
openmp/runtime/src/kmp_runtime.cpp
View File

@ -88,7 +88,7 @@ void __kmp_setup_icv_copy(kmp_team_t *team, int new_nproc,
static int __kmp_load_balance_nproc(kmp_root_t *root, int set_nproc);
#endif
static int __kmp_expand_threads(int nWish, int nNeed);
static int __kmp_expand_threads(int nNeed);
#if KMP_OS_WINDOWS
static int __kmp_unregister_root_other_thread(int gtid);
#endif
@ -941,7 +941,7 @@ static int __kmp_reserve_threads(kmp_root_t *root, kmp_team_t *parent_team,
int slotsRequired = __kmp_nth + new_nthreads -
(root->r.r_active ? 1 : root->r.r_hot_team->t.t_nproc) -
capacity;
int slotsAdded = __kmp_expand_threads(slotsRequired, slotsRequired);
int slotsAdded = __kmp_expand_threads(slotsRequired);
if (slotsAdded < slotsRequired) {
// The threads array was not expanded enough.
new_nthreads -= (slotsRequired - slotsAdded);
@ -3501,22 +3501,16 @@ static int __kmp_reclaim_dead_roots(void) {
__kmpc_threadprivate_cached is done using __kmp_tp_cached_lock.
After any dead root reclamation, if the clipping value allows array expansion
to result in the generation of a total of nWish free slots, the function does
that expansion. If not, but the clipping value allows array expansion to
result in the generation of a total of nNeed free slots, the function does
that expansion. Otherwise, nothing is done beyond the possible initial root
thread reclamation. However, if nNeed is zero, a best-effort attempt is made
to fulfil nWish as far as possible, i.e. the function will attempt to create
as many free slots as possible up to nWish.
to result in the generation of a total of nNeed free slots, the function does
that expansion. If not, nothing is done beyond the possible initial root
thread reclamation.
If any argument is negative, the behavior is undefined. */
static int __kmp_expand_threads(int nWish, int nNeed) {
static int __kmp_expand_threads(int nNeed) {
int added = 0;
int old_tp_cached;
int __kmp_actual_max_nth;
if (nNeed > nWish) /* normalize the arguments */
nWish = nNeed;
#if KMP_OS_WINDOWS && !defined KMP_DYNAMIC_LIB
/* only for Windows static library */
/* reclaim array entries for root threads that are already dead */
@ -3527,13 +3521,8 @@ static int __kmp_expand_threads(int nWish, int nNeed) {
if (nNeed < 0)
nNeed = 0;
}
if (nWish) {
nWish -= added;
if (nWish < 0)
nWish = 0;
}
#endif
if (nWish <= 0)
if (nNeed <= 0)
return added;
while (1) {
@ -3565,25 +3554,11 @@ static int __kmp_expand_threads(int nWish, int nNeed) {
old_tp_cached ? __kmp_tp_capacity : __kmp_sys_max_nth;
KMP_DEBUG_ASSERT(__kmp_actual_max_nth >= __kmp_threads_capacity);
/* compute expansion headroom to check if we can expand and whether to aim
for nWish or nNeed */
nTarget = nWish;
/* compute expansion headroom to check if we can expand */
nTarget = nNeed;
if (__kmp_actual_max_nth - __kmp_threads_capacity < nTarget) {
/* can't fulfil nWish, so try nNeed */
if (nNeed) {
nTarget = nNeed;
if (__kmp_actual_max_nth - __kmp_threads_capacity < nTarget) {
/* possible expansion too small -- give up */
break;
}
} else {
/* best-effort */
nTarget = __kmp_actual_max_nth - __kmp_threads_capacity;
if (!nTarget) {
/* can expand at all -- give up */
break;
}
}
/* possible expansion too small -- give up */
break;
}
minimumRequiredCapacity = __kmp_threads_capacity + nTarget;
@ -3670,7 +3645,7 @@ int __kmp_register_root(int initial_thread) {
}
/* see if there are too many threads */
if (__kmp_all_nth >= capacity && !__kmp_expand_threads(1, 1)) {
if (__kmp_all_nth >= capacity && !__kmp_expand_threads(1)) {
if (__kmp_tp_cached) {
__kmp_fatal(KMP_MSG(CantRegisterNewThread),
KMP_HNT(Set_ALL_THREADPRIVATE, __kmp_tp_capacity),