From: mquinson <mquinson@48e7efb5-ca39-0410-a469-dd3cf9ba447f>
Date: Tue, 10 May 2005 11:08:44 +0000 (+0000)
Subject: Implement real timers to avoid rounding errors when using only current time encoded... 
X-Git-Tag: v3.3~4098
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/832fed2e817aad1deb04971a551b7a5204981d87?hp=d0044d55f406052a8fe431b8ba2eec7d85217dd3

Implement real timers to avoid rounding errors when using only current time encoded as a double


git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@1256 48e7efb5-ca39-0410-a469-dd3cf9ba447f
---

diff --git a/src/include/xbt/xbt_portability.h b/src/include/xbt/xbt_portability.h
index 6a3ef6a859..be1589292f 100644
--- a/src/include/xbt/xbt_portability.h
+++ b/src/include/xbt/xbt_portability.h
@@ -17,4 +17,11 @@
     they really know what they are doing. */
 double xbt_os_time(void);
 
+typedef struct s_xbt_os_timer *xbt_os_timer_t;
+xbt_os_timer_t xbt_os_timer_new(void);
+void xbt_os_timer_free(xbt_os_timer_t timer);
+void xbt_os_timer_start(xbt_os_timer_t timer);
+void xbt_os_timer_stop(xbt_os_timer_t timer);
+double xbt_os_timer_elapsed(xbt_os_timer_t timer);
+
 #endif
diff --git a/src/xbt/sysdep.c b/src/xbt/sysdep.c
index d4199cedb0..6f6aea8b8a 100644
--- a/src/xbt/sysdep.c
+++ b/src/xbt/sysdep.c
@@ -15,6 +15,11 @@
 #include "xbt/error.h"
 #include "portable.h"
 
+
+/* TSC (tick-level) timers are said to be unreliable on SMP hosts and thus 
+   disabled in SDL source code */ 
+
+
 /* \defgroup XBT_sysdep All system dependency
  * \brief This section describes many macros/functions that can serve as
  *  an OS abstraction.
@@ -29,10 +34,43 @@ double xbt_os_time(void) {
   return (double)(tv.tv_sec + tv.tv_usec / 1000000.0);
 #else
   /* Poor resolution */
-  return (double)(time(NULL)); 
+  return (double)(time(NULL));
 #endif /* HAVE_GETTIMEOFDAY? */ 	
 }
 
-
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(sysdep, xbt, "System dependency");
 
+
+struct s_xbt_os_timer {
+#ifdef HAVE_GETTIMEOFDAY
+   struct timeval start,stop;
+#else
+   unsigned long int start,stop;
+#endif
+};
+
+xbt_os_timer_t xbt_os_timer_new(void) {
+   return xbt_new0(struct s_xbt_os_timer,1);
+}
+void xbt_os_timer_free(xbt_os_timer_t timer) {
+   free (timer);
+}
+void xbt_os_timer_start(xbt_os_timer_t timer) {
+#ifdef HAVE_GETTIMEOFDAY
+  gettimeofday(&(timer->start), NULL);
+#else 
+  timer->start = (unsigned long int)(time(NULL));
+#endif
+}
+void xbt_os_timer_stop(xbt_os_timer_t timer) {
+#ifdef HAVE_GETTIMEOFDAY
+  gettimeofday(&(timer->stop), NULL);
+#else 
+  timer->stop = (unsigned long int)(time(NULL));
+#endif
+}
+double xbt_os_timer_elapsed(xbt_os_timer_t timer) {
+   return  ((double)timer->stop.tv_sec)  - ((double)timer->start.tv_sec) +
+         ((((double)timer->stop.tv_usec) - ((double)timer->start.tv_usec)) / 1000000.0);
+}
+