Import changeset

bdb/os_win32/os_spin.c

@@ -0,0 +1,59 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1997, 1998, 1999, 2000
+ *	Sleepycat Software.  All rights reserved.
+ */
+
+#include "db_config.h"
+
+#ifndef lint
+static const char revid[] = "$Id: os_spin.c,v 11.6 2000/05/17 19:30:19 bostic Exp $";
+#endif /* not lint */
+
+#include "db_int.h"
+#include "os_jump.h"
+
+/*
+ * __os_spin --
+ *	Return the number of default spins before blocking.
+ */
+int
+__os_spin()
+{
+	SYSTEM_INFO SystemInfo;
+
+	/*
+	 * If the application specified a value or we've already figured it
+	 * out, return it.
+	 */
+	if (DB_GLOBAL(db_tas_spins) != 0)
+		return (DB_GLOBAL(db_tas_spins));
+
+	/* Get the number of processors */
+	GetSystemInfo(&SystemInfo);
+
+	/*
+	 * Spin 50 times per processor -- we have anecdotal evidence that this
+	 * is a reasonable value.
+	 */
+	if (SystemInfo.dwNumberOfProcessors > 1)
+		 DB_GLOBAL(db_tas_spins) = 50 * SystemInfo.dwNumberOfProcessors;
+	else
+		 DB_GLOBAL(db_tas_spins) = 1;
+	return (DB_GLOBAL(db_tas_spins));
+}
+
+/*
+ * __os_yield --
+ *	Yield the processor.
+ */
+void
+__os_yield(dbenv, usecs)
+	DB_ENV *dbenv;
+	u_long usecs;
+{
+	if (__db_jump.j_yield != NULL && __db_jump.j_yield() == 0)
+		return;
+	__os_sleep(dbenv, 0, usecs);
+}