1 files changed, 109 insertions, 0 deletions
diff --git a/db/os/os_spin.c b/db/os/os_spin.c
new file mode 100644
index 000000000..b0800b988
--- /dev/null
+++ b/db/os/os_spin.c
@@ -0,0 +1,109 @@
+/*-
+ * 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 11.5 2000/03/30 01:46:42 ubell Exp $";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+#if defined(HAVE_PSTAT_GETDYNAMIC)
+#include <sys/pstat.h>
+#endif
+
+#include <limits.h>
+#include <unistd.h>
+#endif
+
+#include "db_int.h"
+#include "os_jump.h"
+
+#if defined(HAVE_PSTAT_GETDYNAMIC)
+/*
+ * __os_pstat_getdynamic --
+ *	HP/UX.
+ */
+static int
+__os_pstat_getdynamic()
+{
+	struct pst_dynamic psd;
+
+	return (pstat_getdynamic(&psd,
+	    sizeof(psd), (size_t)1, 0) == -1 ? 1 : psd.psd_proc_cnt);
+}
+#endif
+
+#if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN)
+/*
+ * __os_sysconf --
+ *	Solaris, Linux.
+ */
+static int
+__os_sysconf()
+{
+	int nproc;
+
+	return ((nproc = sysconf(_SC_NPROCESSORS_ONLN)) > 1 ? nproc : 1);
+}
+#endif
+
+/*
+ * __os_spin --
+ *	Return the number of default spins before blocking.
+ *
+ * PUBLIC: int __os_spin __P((void));
+ */
+int
+__os_spin()
+{
+	/*
+	 * If the application specified a value or we've already figured it
+	 * out, return it.
+	 *
+	 * XXX
+	 * We don't want to repeatedly call the underlying function because
+	 * it can be expensive (e.g., requiring multiple filesystem accesses
+	 * under Debian Linux).
+	 */
+	if (DB_GLOBAL(db_tas_spins) != 0)
+		return (DB_GLOBAL(db_tas_spins));
+
+	DB_GLOBAL(db_tas_spins) = 1;
+#if defined(HAVE_PSTAT_GETDYNAMIC)
+	DB_GLOBAL(db_tas_spins) = __os_pstat_getdynamic();
+#endif
+#if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN)
+	DB_GLOBAL(db_tas_spins) = __os_sysconf();
+#endif
+
+	/*
+	 * Spin 50 times per processor, we have anecdotal evidence that this
+	 * is a reasonable value.
+	 */
+	if (DB_GLOBAL(db_tas_spins) != 1)
+		DB_GLOBAL(db_tas_spins) *= 50;
+
+	return (DB_GLOBAL(db_tas_spins));
+}
+
+/*
+ * __os_yield --
+ *	Yield the processor.
+ *
+ * PUBLIC: void __os_yield __P((DB_ENV*, u_long));
+ */
+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);
+}