8184271: Time related C1 intrinsics produce inconsistent results when floating around
Summary: C1 intrinsics for System.nanoTime(), System.currentTimeMillis() and JVM.counterTime() should be pinned.
Reviewed-by: kvn, vlivanov
--- a/hotspot/src/share/vm/c1/c1_Instruction.hpp Thu Jul 13 15:11:53 2017 +0000
+++ b/hotspot/src/share/vm/c1/c1_Instruction.hpp Fri Jul 14 11:55:58 2017 +0200
@@ -1566,7 +1566,7 @@
set_needs_null_check(has_receiver);
// some intrinsics can't trap, so don't force them to be pinned
- if (!can_trap()) {
+ if (!can_trap() && !vmIntrinsics::should_be_pinned(_id)) {
unpin(PinStateSplitConstructor);
}
}
--- a/hotspot/src/share/vm/classfile/vmSymbols.cpp Thu Jul 13 15:11:53 2017 +0000
+++ b/hotspot/src/share/vm/classfile/vmSymbols.cpp Fri Jul 14 11:55:58 2017 +0200
@@ -399,6 +399,21 @@
}
}
+// Some intrinsics produce different results if they are not pinned
+bool vmIntrinsics::should_be_pinned(vmIntrinsics::ID id) {
+ assert(id != vmIntrinsics::_none, "must be a VM intrinsic");
+ switch(id) {
+#ifdef TRACE_HAVE_INTRINSICS
+ case vmIntrinsics::_counterTime:
+#endif
+ case vmIntrinsics::_currentTimeMillis:
+ case vmIntrinsics::_nanoTime:
+ return true;
+ default:
+ return false;
+ }
+}
+
bool vmIntrinsics::does_virtual_dispatch(vmIntrinsics::ID id) {
assert(id != vmIntrinsics::_none, "must be a VM intrinsic");
switch(id) {
--- a/hotspot/src/share/vm/classfile/vmSymbols.hpp Thu Jul 13 15:11:53 2017 +0000
+++ b/hotspot/src/share/vm/classfile/vmSymbols.hpp Fri Jul 14 11:55:58 2017 +0200
@@ -1632,6 +1632,7 @@
static bool preserves_state(vmIntrinsics::ID id);
static bool can_trap(vmIntrinsics::ID id);
+ static bool should_be_pinned(vmIntrinsics::ID id);
// (2) Information needed by the C2 compiler.
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/c1/TestPinnedIntrinsics.java Fri Jul 14 11:55:58 2017 +0200
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8184271
+ * @summary Test correct scheduling of System.nanoTime and System.currentTimeMillis C1 intrinsics.
+ * @run main/othervm -XX:TieredStopAtLevel=1 -Xbatch
+ * -XX:CompileCommand=dontinline,compiler.c1.TestPinnedIntrinsics::checkNanoTime
+ * -XX:CompileCommand=dontinline,compiler.c1.TestPinnedIntrinsics::checkCurrentTimeMillis
+ * compiler.c1.TestPinnedIntrinsics
+ */
+
+package compiler.c1;
+
+public class TestPinnedIntrinsics {
+
+ private static void testNanoTime() {
+ long start = System.nanoTime();
+ long end = System.nanoTime();
+ checkNanoTime(end - start);
+ }
+
+ private static void checkNanoTime(long diff) {
+ if (diff < 0) {
+ throw new RuntimeException("testNanoTime failed with " + diff);
+ }
+ }
+
+ private static void testCurrentTimeMillis() {
+ long start = System.currentTimeMillis();
+ long end = System.currentTimeMillis();
+ checkCurrentTimeMillis(end - start);
+ }
+
+ private static void checkCurrentTimeMillis(long diff) {
+ if (diff < 0) {
+ throw new RuntimeException("testCurrentTimeMillis failed with " + diff);
+ }
+ }
+
+ public static void main(String[] args) {
+ for (int i = 0; i < 100_000; ++i) {
+ testNanoTime();
+ testCurrentTimeMillis();
+ }
+ }
+}