check that tap device is actually created

[sliver-openvswitch.git] / lib / timeval.h

diff --git a/lib/timeval.h b/lib/timeval.h
index 1384848..72cf498 100644 (file)
--- a/lib/timeval.h
+++ b/lib/timeval.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,7 @@
 extern "C" {
 #endif
 
+struct ds;
 struct pollfd;
 struct timespec;
 struct timeval;
@@ -36,28 +37,25 @@ BUILD_ASSERT_DECL(TYPE_IS_INTEGER(time_t));
  * ever encounter such a platform. */
 BUILD_ASSERT_DECL(TYPE_IS_SIGNED(time_t));
 
-/* On x86-64 systems, Linux avoids using syscalls for clock_gettime().
- *
- * For systems which do invoke a system call we wait at least
- * TIME_UPDATE_INTERVAL ms between clock_gettime() calls and cache the time for
- * the interim.
- *
- * For systems which do not invoke a system call, we just call clock_gettime()
- * whenever the time is requested.  As a result we don't start the background
- * SIGALRM timer unless explicitly needed by time_alarm() */
-#if defined __x86_64__ && defined __linux__
-#define CACHE_TIME 0
-#else
-#define CACHE_TIME 1
-#endif
-
 #define TIME_MAX TYPE_MAXIMUM(time_t)
 #define TIME_MIN TYPE_MINIMUM(time_t)
 
 /* Interval between updates to the reported time, in ms.  This should not be
  * adjusted much below 10 ms or so with the current implementation, or too
  * much time will be wasted in signal handlers and calls to clock_gettime(). */
-#define TIME_UPDATE_INTERVAL 100
+#define TIME_UPDATE_INTERVAL 25
+
+/* True on systems that support a monotonic clock.  Compared to just getting
+ * the value of a variable, clock_gettime() is somewhat expensive, even on
+ * systems that try hard to optimize it (such as x86-64 Linux), so it's
+ * worthwhile to minimize calls via caching. */
+#ifndef CACHE_TIME
+#if defined ESX
+#define CACHE_TIME 0
+#else
+#define CACHE_TIME 1
+#endif
+#endif /* ifndef CACHE_TIME */
 
 void time_disable_restart(void);
 void time_enable_restart(void);
@@ -72,6 +70,7 @@ void time_wall_timespec(struct timespec *);
 void time_alarm(unsigned int secs);
 int time_poll(struct pollfd *, int n_pollfds, long long int timeout_when,
               int *elapsed);
+bool time_cached(void);
 
 long long int timespec_to_msec(const struct timespec *);
 long long int timeval_to_msec(const struct timeval *);
@@ -79,6 +78,7 @@ long long int timeval_to_msec(const struct timeval *);
 void xgettimeofday(struct timeval *);
 
 int get_cpu_usage(void);
+void format_backtraces(struct ds *, size_t min_count);
 
 long long int time_boot_msec(void);