Changeset: 3e35d7b01223 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/3e35d7b01223
Modified Files:
gdk/gdk_bbp.c
Branch: Jul2021
Log Message:
Remove multiple free lists for free bats.
There is actually less contention because there is no longer a single
list that receives most of the free entries while other lists are the
ones that need to produce free entries.
diffs (86 lines):
diff --git a/gdk/gdk_bbp.c b/gdk/gdk_bbp.c
--- a/gdk/gdk_bbp.c
+++ b/gdk/gdk_bbp.c
@@ -110,7 +110,7 @@ struct BBPfarm_t BBPfarms[MAXFARMS];
static MT_Lock BBPnameLock = MT_LOCK_INITIALIZER(BBPnameLock);
static bat *BBP_hash = NULL; /* BBP logical name hash buckets */
static bat BBP_mask = 0; /* number of buckets = & mask */
-#define BBP_THREADMASK 63
+#define BBP_THREADMASK 0 /* originally: 63 */
#if SIZEOF_SIZE_T == 8
#define threadmask(y) ((int) (mix_lng(y) & BBP_THREADMASK))
#else
@@ -1947,6 +1947,7 @@ BBPgetsubdir(str s, bat i)
static gdk_return
maybeextend(int idx)
{
+#if BBP_THREADMASK > 0
int t, m;
int n, l;
bat i;
@@ -1973,6 +1974,7 @@ maybeextend(int idx)
BBP_next(i) = 0;
BBP_free(idx) = i;
} else {
+#endif
/* let the longest list alone, get a fresh entry */
bat size = (bat) ATOMIC_GET(&BBPsize);
if (size >= BBPlimit &&
@@ -1980,13 +1982,16 @@ maybeextend(int idx)
/* couldn't extend; if there is any
* free entry, take it from the
* longest list after all */
+#if BBP_THREADMASK > 0
if (l > 0) {
i = BBP_free(m);
BBP_free(m) = BBP_next(i);
BBP_next(i) = 0;
BBP_free(idx) = i;
GDKclrerr();
- } else {
+ } else
+#endif
+ {
/* nothing available */
return GDK_FAIL;
}
@@ -1994,8 +1999,10 @@ maybeextend(int idx)
ATOMIC_SET(&BBPsize, size + 1);
BBP_free(idx) = size;
}
+#if BBP_THREADMASK > 0
}
last = (last + 1) & BBP_THREADMASK;
+#endif
return GDK_SUCCEED;
}
@@ -2018,6 +2025,7 @@ BBPinsert(BAT *bn)
if (BBP_free(idx) <= 0) {
/* we need to extend the BBP */
gdk_return r = GDK_SUCCEED;
+#if BBP_THREADMASK > 0
if (lock) {
/* we must take all locks in a consistent
* order so first unset the one we've already
@@ -2026,6 +2034,7 @@ BBPinsert(BAT *bn)
for (i = 0; i <= BBP_THREADMASK; i++)
MT_lock_set(&GDKcacheLock(i));
}
+#endif
MT_lock_set(&BBPnameLock);
/* check again in case some other thread extended
* while we were waiting */
@@ -2033,10 +2042,12 @@ BBPinsert(BAT *bn)
r = maybeextend(idx);
}
MT_lock_unset(&BBPnameLock);
+#if BBP_THREADMASK > 0
if (lock)
for (i = BBP_THREADMASK; i >= 0; i--)
if (i != idx)
MT_lock_unset(&GDKcacheLock(i));
+#endif
if (r != GDK_SUCCEED) {
if (lock) {
MT_lock_unset(&GDKcacheLock(idx));
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