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7117303: VM uses non-monotonic time source and complains that it is non-monotonic

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Replaces calls to os::javaTimeMillis(), which does not (and cannot) guarantee monotonicity, in GC code to an equivalent expression that uses os::javaTimeNanos(). os::javaTimeNanos is guaranteed monotonically non-decreasing if the underlying platform provides a monotonic time source. Changes in OS files are to make use of the newly defined constants in globalDefinitions.hpp.

Reviewed-by: dholmes, ysr
This commit is contained in:
John Cuthbertson 2011-12-19 10:02:05 -08:00
parent 2768349b41
commit 870bea622a
10 changed files with 57 additions and 57 deletions
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11
hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp
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@ -3398,17 +3398,22 @@ PSParallelCompact::move_and_update(ParCompactionManager* cm, SpaceId space_id) {
}
jlong PSParallelCompact::millis_since_last_gc() {
jlong ret_val = os::javaTimeMillis() - _time_of_last_gc;
// We need a monotonically non-deccreasing time in ms but
// os::javaTimeMillis() does not guarantee monotonicity.
jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
jlong ret_val = now - _time_of_last_gc;
// XXX See note in genCollectedHeap::millis_since_last_gc().
if (ret_val < 0) {
NOT_PRODUCT(warning("time warp: %d", ret_val);)
NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);)
return 0;
}
return ret_val;
}
void PSParallelCompact::reset_millis_since_last_gc() {
_time_of_last_gc = os::javaTimeMillis();
// We need a monotonically non-deccreasing time in ms but
// os::javaTimeMillis() does not guarantee monotonicity.
_time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
}
ParMarkBitMap::IterationStatus MoveAndUpdateClosure::copy_until_full()