Changeset: 17cc705cf1e8 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=17cc705cf1e8
Modified Files:
monetdb5/mal/mal_resource.c
Branch: Feb2013
Log Message:
Use atomic instructions to maintain running count.
diffs (59 lines):
diff --git a/monetdb5/mal/mal_resource.c b/monetdb5/mal/mal_resource.c
--- a/monetdb5/mal/mal_resource.c
+++ b/monetdb5/mal/mal_resource.c
@@ -170,7 +170,11 @@ MALadmission(lng argclaim, lng hotclaim)
* By keeping the query start time in the client record we can delay
* them when resource stress occurs.
*/
-static int running; /* should be protected, but no need for accurateness here.
saving locks */
+#include "gdk_atomic.h"
+static volatile ATOMIC_TYPE running;
+#ifdef ATOMIC_LOCK
+static MT_Lock runningLock = ATOMIC_LOCK;
+#endif
void
MALresourceFairness(Client cntxt, MalBlkPtr mb, lng usec)
@@ -184,8 +188,10 @@ MALresourceFairness(Client cntxt, MalBlk
if ( usec > 0 && ( (usec = GDKusec()-usec)) <= TIMESLICE )
return;
threads= GDKnr_threads > 0? GDKnr_threads: 1;
+ ATOMIC_START(runningLock, "MALresourceFairness");
if ( running == 0) // reset workers pool count
running = threads;
+ ATOMIC_END(runningLock, "MALresourceFairness");
/* use GDKmem_cursize as MT_getrss(); is to expensive */
rss = GDKmem_cursize();
@@ -209,7 +215,7 @@ MALresourceFairness(Client cntxt, MalBlk
PARDEBUG mnstr_printf(GDKstdout, "#delay %d initial "LLFMT"n",
cntxt->idx, clk);
while (clk > 0) {
/* always keep one running to avoid all waiting */
- if (running < 2)
+ if (ATOMIC_GET(running, runningLock,
"MALresourceFairness") < 2)
break;
/* speed up wake up when we have memory */
rss = GDKmem_cursize();
@@ -217,8 +223,10 @@ MALresourceFairness(Client cntxt, MalBlk
break;
factor = ((double) rss) / (MEMORY_THRESHOLD *
monet_memory);
delay = (lng) (DELAYUNIT * (factor > 1.0 ? 1.0 :
factor));
+ ATOMIC_START(runningLock, "MALresourceFairness");
delay = (lng) ( ((double)delay) * running / threads);
- running--;
+ ATOMIC_DEC(running);
+ ATOMIC_END(runningLock, "MALresourceFairness");
if (delay) {
if ( delayed++ == 0){
mnstr_printf(GDKstdout, "#delay
%d initial "LLFMT"["LLFMT"] memory "SZFMT"[%f]\n", cntxt->idx, delay, clk,
rss, MEMORY_THRESHOLD * monet_memory);
@@ -226,7 +234,9 @@ MALresourceFairness(Client cntxt, MalBlk
}
MT_sleep_ms(delay);
}
- running++;
+ ATOMIC_START(runningLock, "MALresourceFairness");
+ ATOMIC_INC(running);
+ ATOMIC_END(runningLock, "MALresourceFairness");
clk -= DELAYUNIT;
}
}
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