Changeset: 20a08cf056b8 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/20a08cf056b8
Modified Files:
gdk/gdk_sample.c
Branch: default
Log Message:
The random number generator (next()) is not reentrant, so use private state.
diffs (82 lines):
diff --git a/gdk/gdk_sample.c b/gdk/gdk_sample.c
--- a/gdk/gdk_sample.c
+++ b/gdk/gdk_sample.c
@@ -98,7 +98,7 @@ OIDTreeToBATAntiset(struct oidtreenode *
}
static BAT *
-do_batsample(oid hseq, BUN cnt, BUN n, random_state_engine rse, MT_Lock *lock)
+do_batsample(oid hseq, BUN cnt, BUN n, random_state_engine rse)
{
BAT *bn;
BUN slen;
@@ -204,34 +204,15 @@ do_batsample(oid hseq, BUN cnt, BUN n, r
return NULL;
}
- if (lock)
- MT_lock_set(lock);
- /* generate a list of random numbers; note we use the
- * "tree" array, but we use the value from each location
- * before it is overwritten by the use as part of the
- * binary tree */
- for (rescnt = 0; rescnt < n; rescnt++)
- tree[rescnt].r = next(rse);
-
/* while we do not have enough sample OIDs yet */
- BUN rnd = 0;
for (rescnt = 0; rescnt < n; rescnt++) {
oid candoid;
do {
- if (rnd == n) {
- /* we ran out of random numbers,
- * so generate more */
- for (rnd = rescnt; rnd < n; rnd++)
- tree[rnd].r = next(rse);
- rnd = rescnt;
- }
- candoid = minoid + tree[rnd++].r % cnt;
+ candoid = minoid + next(rse) % cnt;
/* if that candidate OID was already
* generated, try again */
} while (!OIDTreeMaybeInsert(tree, candoid, rescnt));
}
- if (lock)
- MT_lock_unset(lock);
if (!antiset) {
OIDTreeToBAT(tree, bn);
} else {
@@ -258,31 +239,15 @@ BATsample_with_seed(BAT *b, BUN n, uint6
TRC_DEBUG_IF(ALGO) t0 = GDKusec();
init_random_state_engine(rse, seed);
- BAT *bn = do_batsample(b->hseqbase, BATcount(b), n, rse, NULL);
+ BAT *bn = do_batsample(b->hseqbase, BATcount(b), n, rse);
TRC_DEBUG(ALGO, ALGOBATFMT "," BUNFMT " -> " ALGOOPTBATFMT
" (" LLFMT " usec)\n",
ALGOBATPAR(b), n, ALGOOPTBATPAR(bn), GDKusec() - t0);
return bn;
}
-static MT_Lock rse_lock = MT_LOCK_INITIALIZER(rse_lock);
BAT *
BATsample(BAT *b, BUN n)
{
- static random_state_engine rse;
- lng t0 = 0;
-
- TRC_DEBUG_IF(ALGO) t0 = GDKusec();
- MT_lock_set(&b->theaplock);
- BUN batcount = BATcount(b);
- MT_lock_unset(&b->theaplock);
- MT_lock_set(&rse_lock);
- if (rse[0] == 0 && rse[1] == 0 && rse[2] == 0 && rse[3] == 0)
- init_random_state_engine(rse, (uint64_t) GDKusec());
- MT_lock_unset(&rse_lock);
- BAT *bn = do_batsample(b->hseqbase, batcount, n, rse, &rse_lock);
- TRC_DEBUG(ALGO, ALGOBATFMT "," BUNFMT " -> " ALGOOPTBATFMT
- " (" LLFMT " usec)\n",
- ALGOBATPAR(b), n, ALGOOPTBATPAR(bn), GDKusec() - t0);
- return bn;
+ return BATsample_with_seed(b, n, (uint64_t) GDKusec());
}
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