X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Ftimeval.h;h=cb5191c5ee26fdaa3e3fab513221ee2aa331516f;hb=f606c7e99465477cf0533ecbc4795a0f8fe635e0;hp=e57f7ac7b83aa6147eb8343dd6b0ab3ef61fb4eb;hpb=cee03df4f53a9629f1f18b6c9948362f55a3ae27;p=openvswitch

diff --git a/lib/timeval.h b/lib/timeval.h
index e57f7ac7..cb5191c5 100644
--- a/lib/timeval.h
+++ b/lib/timeval.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -44,6 +44,22 @@ BUILD_ASSERT_DECL(TYPE_IS_SIGNED(time_t));
  * much time will be wasted in signal handlers and calls to clock_gettime(). */
 #define TIME_UPDATE_INTERVAL 100
 
+/* True on systems (particularly x86-64 Linux) where clock_gettime() is
+ * inexpensive.  On these systems, we don't bother caching the current time.
+ * Instead, we consult clock_gettime() directly when needed.
+ *
+ * False on systems where clock_gettime() is relatively expensive.  On these
+ * systems, we cache the current time and set up a periodic SIGALRM to remind
+ * us to update it.
+ *
+ * Also false on systems (e.g. ESX) that don't support setting up timers based
+ * on a monotonically increasing clock. */
+#if defined ESX || (defined __x86_64__ && defined LINUX_DATAPATH)
+#define CACHE_TIME 0
+#else
+#define CACHE_TIME 1
+#endif
+
 void time_disable_restart(void);
 void time_enable_restart(void);
 void time_postfork(void);
@@ -57,6 +73,7 @@ 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 *);
@@ -65,6 +82,8 @@ void xgettimeofday(struct timeval *);
 
 int get_cpu_usage(void);
 
+long long int time_boot_msec(void);
+
 #ifdef  __cplusplus
 }
 #endif