src/os/windows/vm/os_windows.cpp

Print this page
rev 2869 : 7117303: VM uses non-monotonic time source and complains that it is non-monotonic
Summary: Replaces calls to os::javaTimeMillis(), which does not guarantee montonicity, in GC code to os::javaTimeNanos() with a suitable conversion factor. os::javaTimeNanos() mostly guarantees montonicity depending on the underlying OS implementation and, as a result, a better alternative. Changes in OS files are to make use of the newly defined constants in globalDefinitions.hpp.
Reviewed-by:

@@ -819,21 +819,19 @@
     GetSystemTimeAsFileTime(&wt);
     return windows_to_java_time(wt);
   }
 }
 
-#define NANOS_PER_SEC         CONST64(1000000000)
-#define NANOS_PER_MILLISEC    1000000
 jlong os::javaTimeNanos() {
   if (!has_performance_count) {
-    return javaTimeMillis() * NANOS_PER_MILLISEC; // the best we can do.
+    return javaTimeMillis() * NANOSECS_PER_MILLISEC; // the best we can do.
   } else {
     LARGE_INTEGER current_count;
     QueryPerformanceCounter(&current_count);
     double current = as_long(current_count);
     double freq = performance_frequency;
-    jlong time = (jlong)((current/freq) * NANOS_PER_SEC);
+    jlong time = (jlong)((current/freq) * NANOSECS_PER_SEC);
     return time;
   }
 }
 
 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {

@@ -845,19 +843,19 @@
     // this is a wall clock timer, so may skip
     info_ptr->may_skip_backward = true;
     info_ptr->may_skip_forward = true;
   } else {
     jlong freq = performance_frequency;
-    if (freq < NANOS_PER_SEC) {
+    if (freq < NANOSECS_PER_SEC) {
       // the performance counter is 64 bits and we will
       // be multiplying it -- so no wrap in 64 bits
       info_ptr->max_value = ALL_64_BITS;
-    } else if (freq > NANOS_PER_SEC) {
+    } else if (freq > NANOSECS_PER_SEC) {
       // use the max value the counter can reach to
       // determine the max value which could be returned
       julong max_counter = (julong)ALL_64_BITS;
-      info_ptr->max_value = (jlong)(max_counter / (freq / NANOS_PER_SEC));
+      info_ptr->max_value = (jlong)(max_counter / (freq / NANOSECS_PER_SEC));
     } else {
       // the performance counter is 64 bits and we will
       // be using it directly -- so no wrap in 64 bits
       info_ptr->max_value = ALL_64_BITS;
     }