bk commit into 6.0 tree (jas:1.2672)

[Jim Starkey]

Below is the list of changes that have just been committed into a local
6.0 repository of jas.  When jas does a push these changes
will be propagated to the main repository and, within 24 hours after the
push, to the public repository.
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see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet@stripped, 2008-05-14 18:31:23-04:00, jas@stripped +2 -0
  Played around with SyncObject backoff strategy.

  storage/falcon/SyncObject.cpp@stripped, 2008-05-14 18:31:19-04:00, jas@stripped +4 -3
    Played around with SyncObject backoff strategy.

  storage/falcon/SyncTest.cpp@stripped, 2008-05-14 18:31:19-04:00, jas@stripped +6 -1
    Eliminated some detail from report; added average number
    of successful cycles.

diff -Nrup a/storage/falcon/SyncObject.cpp b/storage/falcon/SyncObject.cpp
--- a/storage/falcon/SyncObject.cpp	2008-05-14 15:48:42 -04:00
+++ b/storage/falcon/SyncObject.cpp	2008-05-14 18:31:19 -04:00
@@ -55,7 +55,7 @@
 		else\
 			{ thread = Thread::getThread("SyncObject::lock"); thread->backoff = BACKOFF_INTERVAL; }
 
-#define BACKOFF_INTERVAL	(thread->random % 100)
+#define BACKOFF_INTERVAL	(thread->random % 1000)
 
 #ifdef TRACE_SYNC_OBJECTS
 
@@ -733,9 +733,10 @@ int SyncObject::getCollisionCount(void)
 void SyncObject::backoff(Thread* thread)
 {
 	//thread->sleep(1);
+    int a = 0;
 
 	for (int n = 0; n < thread->backoff; ++n)
-		;
+		++a;
 	
-	thread->backoff += thread->backoff;
+	thread->backoff += a;
 }
diff -Nrup a/storage/falcon/SyncTest.cpp b/storage/falcon/SyncTest.cpp
--- a/storage/falcon/SyncTest.cpp	2008-05-14 15:48:43 -04:00
+++ b/storage/falcon/SyncTest.cpp	2008-05-14 18:31:19 -04:00
@@ -43,6 +43,7 @@ void SyncTest::test()
 	
 	Sync sync(&starter, "SyncTest::test");
 	Threads *threadBarn = new Threads(NULL, MAX_THREADS);
+	int grandTotal = 0;
 		
 	for (int n = 1; n <= MAX_THREADS; ++n)
 		{
@@ -85,14 +86,18 @@ void SyncTest::test()
 		for (thd = 0; thd < n; ++thd)
 			total += threads[thd].count;
 		
-		printf("%d threads, %d cycles, %d collisions:", n, total, syncObject.getCollisionCount() - collisions);
+		grandTotal += total;
+		printf("%d threads, %d cycles, %d collisions\n", n, total, syncObject.getCollisionCount() - collisions);
 
+		/***
 		for (thd = 0; thd < n; ++thd)
 			printf(" %d", threads[thd].count);
 					
 		printf("\n");
+		***/
 		}
 	
+	printf ("Average cycles %d\n", grandTotal / MAX_THREADS);
 	threadBarn->shutdownAll();
 	threadBarn->waitForAll();
 	threadBarn->release();