Changeset: 82770f91d174 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/82770f91d174
Modified Files:
gdk/gdk_bbp.c
gdk/gdk_private.h
gdk/gdk_utils.c
Branch: multi-cachelock
Log Message:
Partition the GDKcacheLock and improve the BBP allocation algorithm
diffs (truncated from 333 to 300 lines):
diff --git a/gdk/gdk_bbp.c b/gdk/gdk_bbp.c
--- a/gdk/gdk_bbp.c
+++ b/gdk/gdk_bbp.c
@@ -110,8 +110,18 @@ 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 */
-static MT_Lock GDKcacheLock = MT_LOCK_INITIALIZER(GDKcacheLock);
-static bat BBP_free;
+#define BBP_THREADMASK 64
+#if SIZEOF_SIZE_T == 8
+#define threadmask(y) ((int) (mix_lng(y) & BBP_THREADMASK))
+#else
+#define threadmask(y) ((int) (mix_int(y) & BBP_THREADMASK))
+#endif
+static struct {
+ MT_Lock cache;
+ bat free;
+} GDKbbpLock[BBP_THREADMASK + 1];
+#define GDKcacheLock(y) GDKbbpLock[y].cache
+#define BBP_free(y) GDKbbpLock[y].free
static gdk_return BBPfree(BAT *b);
static void BBPdestroy(BAT *b);
@@ -281,7 +291,8 @@ BBPlock(void)
}
MT_lock_set(&GDKtmLock);
- MT_lock_set(&GDKcacheLock);
+ for (i = 0; i <= BBP_THREADMASK; i++)
+ MT_lock_set(&GDKcacheLock(i));
for (i = 0; i <= BBP_BATMASK; i++)
MT_lock_set(&GDKswapLock(i));
locked_by = MT_getpid();
@@ -296,14 +307,16 @@ BBPunlock(void)
for (i = BBP_BATMASK; i >= 0; i--)
MT_lock_unset(&GDKswapLock(i));
- MT_lock_unset(&GDKcacheLock);
+ for (i = BBP_THREADMASK; i >= 0; i--)
+ MT_lock_unset(&GDKcacheLock(i));
locked_by = 0;
MT_lock_unset(&GDKtmLock);
}
static gdk_return
-BBPinithash(bat size)
+BBPinithash(int j, bat size)
{
+ assert(j >= 0 && j <= BBP_THREADMASK);
for (BBP_mask = 1; (BBP_mask << 1) <= BBPlimit; BBP_mask <<= 1)
;
BBP_hash = (bat *) GDKzalloc(BBP_mask * sizeof(bat));
@@ -320,8 +333,10 @@ BBPinithash(bat size)
BBP_insert(size);
}
} else {
- BBP_next(size) = BBP_free;
- BBP_free = size;
+ BBP_next(size) = BBP_free(j);
+ BBP_free(j) = size;
+ if (++j > BBP_THREADMASK)
+ j = 0;
}
}
return GDK_SUCCEED;
@@ -355,7 +370,7 @@ BBPselectfarm(role_t role, int type, enu
}
static gdk_return
-BBPextend(bool buildhash, bat newsize)
+BBPextend(int idx, bool buildhash, bat newsize)
{
if (newsize >= N_BBPINIT * BBPINIT) {
GDKerror("trying to extend BAT pool beyond the "
@@ -380,10 +395,12 @@ BBPextend(bool buildhash, bat newsize)
}
if (buildhash) {
+ int i;
GDKfree(BBP_hash);
BBP_hash = NULL;
- BBP_free = 0;
- if (BBPinithash(newsize) != GDK_SUCCEED)
+ for (i = 0; i <= BBP_THREADMASK; i++)
+ BBP_free(i) = 0;
+ if (BBPinithash(idx, newsize) != GDK_SUCCEED)
return GDK_FAIL;
}
return GDK_SUCCEED;
@@ -774,7 +791,7 @@ BBPreadEntries(FILE *fp, unsigned bbpver
if (b.batCacheid >= (bat) ATOMIC_GET(&BBPsize)) {
if ((bat) ATOMIC_GET(&BBPsize) + 1 >= BBPlimit &&
- BBPextend(false, b.batCacheid + 1) != GDK_SUCCEED)
+ BBPextend(0, false, b.batCacheid + 1) !=
GDK_SUCCEED)
goto bailout;
ATOMIC_SET(&BBPsize, b.batCacheid + 1);
}
@@ -1520,7 +1537,7 @@ BBPmanager(void *dummy)
static MT_Id manager;
gdk_return
-BBPinit(void)
+BBPinit(bool first)
{
FILE *fp = NULL;
struct stat st;
@@ -1545,6 +1562,15 @@ BBPinit(void)
* array */
static_assert((uint64_t) N_BBPINIT * BBPINIT < (UINT64_C(1) << (3 *
(sizeof(BBP[0][0].bak) - 5))), "\"bak\" array in BBPrec is too small");
+ if (first) {
+ for (i = 0; i <= BBP_THREADMASK; i++) {
+ char name[MT_NAME_LEN];
+ snprintf(name, sizeof(name), "GDKcacheLock%d", i);
+ MT_lock_init(&GDKbbpLock[i].cache, name);
+ GDKbbpLock[i].free = 0;
+ }
+ }
+
if (!GDKinmemory(0)) {
str bbpdirstr, backupbbpdirstr;
@@ -1662,7 +1688,7 @@ BBPinit(void)
}
/* allocate BBP records */
- if (BBPextend(false, bbpsize) != GDK_SUCCEED) {
+ if (BBPextend(0, false, bbpsize) != GDK_SUCCEED) {
GDKdebug = dbg;
return GDK_FAIL;
}
@@ -1681,7 +1707,7 @@ BBPinit(void)
}
MT_lock_set(&BBPnameLock);
- if (BBPinithash((bat) ATOMIC_GET(&BBPsize)) != GDK_SUCCEED) {
+ if (BBPinithash(0, (bat) ATOMIC_GET(&BBPsize)) != GDK_SUCCEED) {
TRC_CRITICAL(GDK, "BBPinithash failed");
MT_lock_unset(&BBPnameLock);
#ifdef GDKLIBRARY_HASHASH
@@ -2354,26 +2380,49 @@ BBPgetsubdir(str s, bat i)
*s = 0;
}
-/* The free list is empty. We create a new entry by either just
- * increasing BBPsize (up to BBPlimit) or extending the BBP (which
- * increases BBPlimit).
- *
- * Note that this is the only place in normal, multi-threaded operation
- * where BBPsize is assigned a value (never decreasing), that the
- * assignment happens after any necessary memory was allocated and
- * initialized, and that this happens when the BBPnameLock is held. */
+/*
+ * Extends the bpp list of some thread by reserving from the common pool,
+ * increasing the common pool if it runs out of space.
+ */
static gdk_return
-maybeextend(void)
-{
+extendThreadBbpList(int idx) {
+ /* release the current gdkcachelock first to avoid dealocks when
extending the common pool */
+ MT_lock_unset(&GDKcacheLock(idx));
+ MT_lock_set(&BBPnameLock);
+ MT_lock_set(&GDKcacheLock(idx));
+
+ /* thread list was already extended by another concurrent transaction */
+ if (BBP_free(idx) > 0) {
+ MT_lock_unset(&BBPnameLock);
+ return GDK_SUCCEED;
+ }
+
bat size = (bat) ATOMIC_GET(&BBPsize);
- if (size >= BBPlimit &&
- BBPextend(true, size + 1) != GDK_SUCCEED) {
- /* nothing available */
- return GDK_FAIL;
- } else {
- ATOMIC_SET(&BBPsize, size + 1);
- BBP_free = size;
+ /* if the common pool has no more space, extend it */
+ if (size >= BBPlimit) {
+ /* acquire all gdkcachelocks in the same order */
+ for (int i = 0; i <= BBP_THREADMASK; i++) {
+ if (i != idx) {
+ MT_lock_set(&GDKcacheLock(i));
+ }
+ }
+ /* extend the common pool */
+ gdk_return r = BBPextend(idx, true, size + 1);
+ /* release all gdkcachelocks */
+ for (int i = BBP_THREADMASK; i >= 0; i--) {
+ if (i != idx) {
+ MT_lock_unset(&GDKcacheLock(i));
+ }
+ }
+ if (r != GDK_SUCCEED) {
+ return GDK_FAIL;
+ }
}
+ ATOMIC_SET(&BBPsize, size + 1);
+
+ /* extend the thread list */
+ BBP_free(idx) = size;
+ MT_lock_unset(&BBPnameLock);
return GDK_SUCCEED;
}
@@ -2386,36 +2435,28 @@ BBPinsert(BAT *bn)
char dirname[24];
bat i;
int len = 0;
+ int idx = threadmask(pid);
/* critical section: get a new BBP entry */
if (lock) {
- MT_lock_set(&GDKcacheLock);
+ MT_lock_set(&GDKcacheLock(idx));
}
- /* find an empty slot */
- if (BBP_free <= 0) {
- /* we need to extend the BBP */
- gdk_return r = GDK_SUCCEED;
- MT_lock_set(&BBPnameLock);
- /* check again in case some other thread extended
- * while we were waiting */
- if (BBP_free <= 0) {
- r = maybeextend();
- }
- MT_lock_unset(&BBPnameLock);
+ if (BBP_free(idx) <= 0) {
+ /* does not have free ids, get from the common pool */
+ gdk_return r = extendThreadBbpList(idx);
if (r != GDK_SUCCEED) {
- if (lock) {
- MT_lock_unset(&GDKcacheLock);
- }
+ GDKerror("Extend BBplist failed.\n");
return 0;
}
}
- i = BBP_free;
+
+ i = BBP_free(idx);
assert(i > 0);
- BBP_free = BBP_next(i);
+ BBP_free(idx) = BBP_next(i);
if (lock) {
- MT_lock_unset(&GDKcacheLock);
+ MT_lock_unset(&GDKcacheLock(idx));
}
/* rest of the work outside the lock */
@@ -2523,13 +2564,13 @@ BBPuncacheit(bat i, bool unloaddesc)
* BBPclear removes a BAT from the BBP directory forever.
*/
static inline void
-bbpclear(bat i, bool lock)
+bbpclear(bat i, int idx, bool lock)
{
TRC_DEBUG(BAT_, "clear %d (%s)\n", (int) i, BBP_logical(i));
BBPuncacheit(i, true);
TRC_DEBUG(BAT_, "set to unloading %d\n", i);
if (lock) {
- MT_lock_set(&GDKcacheLock);
+ MT_lock_set(&GDKcacheLock(idx));
MT_lock_set(&GDKswapLock(i));
}
@@ -2547,19 +2588,20 @@ bbpclear(bat i, bool lock)
GDKfree(BBP_logical(i));
BBP_status_set(i, 0);
BBP_logical(i) = NULL;
- BBP_next(i) = BBP_free;
- BBP_free = i;
+ BBP_next(i) = BBP_free(idx);
+ BBP_free(idx) = i;
BBP_pid(i) = ~(MT_Id)0; /* not zero, not a valid thread id */
if (lock)
- MT_lock_unset(&GDKcacheLock);
+ MT_lock_unset(&GDKcacheLock(idx));
}
void
BBPclear(bat i, bool lock)
{
- lock &= locked_by == 0 || locked_by != MT_getpid();
+ MT_Id pid = MT_getpid();
+ lock &= locked_by == 0 || locked_by != pid;
if (BBPcheck(i)) {
- bbpclear(i, lock);
+ bbpclear(i, threadmask(pid), lock);
}
}
@@ -4381,7 +4423,9 @@ gdk_bbp_reset(void)
{
_______________________________________________
checkin-list mailing list -- [email protected]
To unsubscribe send an email to [email protected]
