Changeset: 3dede3c5aafc for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=3dede3c5aafc
Modified Files:
gdk/gdk_bbp.c
Branch: Feb2013
Log Message:
Reduce multi-core spin loops
There were a few 1ms spin loops, which in a multi-threaded environment
might cause excessive kernel calls. There impact has been reduced
by making the spinlock dependent on the number of cores.
diffs (38 lines):
diff --git a/gdk/gdk_bbp.c b/gdk/gdk_bbp.c
--- a/gdk/gdk_bbp.c
+++ b/gdk/gdk_bbp.c
@@ -100,6 +100,7 @@ BBPrec *BBP[N_BBPINIT]; /* fixed base V
bat BBPlimit = 0; /* current committed VM BBP array */
bat BBPsize = 0; /* current used size of BBP array */
+#define KITTENNAP 2 * GDKnr_threads /* used to suspend processing */
#define BBPNONAME "." /* filler for no name in BBP.dir */
/*
* The hash index uses a bucket index (int array) of size mask that is
@@ -1926,7 +1927,7 @@ BBPspin(bat i, str s, int event)
lng spin = LL_CONSTANT(0);
while (BBP_status(i) & event) {
- MT_sleep_ms(1);
+ MT_sleep_ms(KITTENNAP);
spin++;
}
BATDEBUG THRprintf(GDKstdout, "#BBPspin(%d,%s,%d): " LLFMT "
loops\n", (int) i, s, event, spin);
@@ -1961,7 +1962,7 @@ incref(bat i, int logical, int lock)
break;
/* the BATs is "unstable", try again */
MT_lock_unset(&GDKswapLock(i), "BBPincref");
- MT_sleep_ms(1);
+ MT_sleep_ms(KITTENNAP);
}
}
/* we have the lock */
@@ -2306,7 +2307,7 @@ getBBPdescriptor(bat i, int lock)
while (BBP_status(j) & BBPWAITING) { /* wait for bat to be
loaded by other thread */
if (lock)
MT_lock_unset(&GDKswapLock(j), "BBPdescriptor");
- MT_sleep_ms(1);
+ MT_sleep_ms(KITTENNAP);
if (lock)
MT_lock_set(&GDKswapLock(j), "BBPdescriptor");
}
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