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8325449: [BACKOUT] use "dmb.ishst+dmb.ishld" for release barrier

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Reviewed-by: chagedorn
This commit is contained in:
Tobias Hartmann 2024-02-14 07:34:28 +00:00
parent 7f6bb71eb3
commit ea98de63f7
5 changed files with 10 additions and 108 deletions
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7
src/hotspot/cpu/aarch64/aarch64.ad
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@ -8289,7 +8289,7 @@ instruct membar_acquire() %{
ins_cost(VOLATILE_REF_COST);
format %{ "membar_acquire\n\t"
"dmb ishld" %}
"dmb ish" %}
ins_encode %{
__ block_comment("membar_acquire");
@ -8343,12 +8343,11 @@ instruct membar_release() %{
ins_cost(VOLATILE_REF_COST);
format %{ "membar_release\n\t"
"dmb ishst\n\tdmb ishld" %}
"dmb ish" %}
ins_encode %{
__ block_comment("membar_release");
__ membar(Assembler::StoreStore);
__ membar(Assembler::LoadStore);
__ membar(Assembler::LoadStore|Assembler::StoreStore);
%}
ins_pipe(pipe_serial);
%}

2
src/hotspot/cpu/aarch64/globals_aarch64.hpp
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@ -127,8 +127,6 @@ define_pd_global(intx, InlineSmallCode, 1000);
range(1, 99) \
product(ccstr, UseBranchProtection, "none", \
"Branch Protection to use: none, standard, pac-ret") \
product(bool, AlwaysMergeDMB, false, DIAGNOSTIC, \
"Always merge DMB instructions in code emission") \
// end of ARCH_FLAGS

21
src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp
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@ -2066,21 +2066,14 @@ void MacroAssembler::membar(Membar_mask_bits order_constraint) {
address last = code()->last_insn();
if (last != nullptr && nativeInstruction_at(last)->is_Membar() && prev == last) {
NativeMembar *bar = NativeMembar_at(prev);
// Don't promote DMB ST|DMB LD to DMB (a full barrier) because
// doing so would introduce a StoreLoad which the caller did not
// intend
if (AlwaysMergeDMB || bar->get_kind() == order_constraint
|| bar->get_kind() == AnyAny
|| order_constraint == AnyAny) {
// We are merging two memory barrier instructions. On AArch64 we
// can do this simply by ORing them together.
bar->set_kind(bar->get_kind() | order_constraint);
BLOCK_COMMENT("merged membar");
return;
}
// We are merging two memory barrier instructions. On AArch64 we
// can do this simply by ORing them together.
bar->set_kind(bar->get_kind() | order_constraint);
BLOCK_COMMENT("merged membar");
} else {
code()->set_last_insn(pc());
dmb(Assembler::barrier(order_constraint));
}
code()->set_last_insn(pc());
dmb(Assembler::barrier(order_constraint));
}
bool MacroAssembler::try_merge_ldst(Register rt, const Address &adr, size_t size_in_bytes, bool is_store) {

3
src/hotspot/cpu/aarch64/vm_version_aarch64.cpp
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@ -191,9 +191,6 @@ void VM_Version::initialize() {
if (FLAG_IS_DEFAULT(UseSIMDForMemoryOps)) {
FLAG_SET_DEFAULT(UseSIMDForMemoryOps, true);
}
if (FLAG_IS_DEFAULT(AlwaysMergeDMB)) {
FLAG_SET_DEFAULT(AlwaysMergeDMB, true);
}
}
// Cortex A53

85
test/micro/org/openjdk/bench/vm/compiler/FinalFieldInitialize.java
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@ -1,85 +0,0 @@
/*
* Copyright (c) 2024, Alibaba Group Co., Ltd. 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.
*/
package org.openjdk.bench.vm.compiler;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.*;
import java.util.concurrent.TimeUnit;
import org.openjdk.jmh.infra.Blackhole;
/* test allocation speed of object with final field */
@BenchmarkMode(Mode.Throughput)
@OutputTimeUnit(TimeUnit.SECONDS)
@State(Scope.Benchmark)
@Warmup(iterations = 5, time = 3, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 3, time = 3, timeUnit = TimeUnit.SECONDS)
@Fork(value = 3)
public class FinalFieldInitialize {
final static int LEN = 100_000;
Object arr[] = null;
@Setup
public void setup(){
arr = new Object[LEN];
}
@Benchmark
public void testAlloc(Blackhole bh) {
for (int i=0; i<LEN; i++) {
arr[i] = new TObj();
}
bh.consume(arr);
}
@Benchmark
public void testAllocWithFinal(Blackhole bh) {
for (int i=0; i<LEN; i++) {
arr[i] = new TObjWithFinal();
}
bh.consume(arr);
}
}
class TObj {
private int i;
private long l;
private boolean b;
public TObj() {
i = 10;
l = 100L;
b = true;
}
}
class TObjWithFinal {
private int i;
private long l;
private final boolean b;
public TObjWithFinal() {
i = 10;
l = 100L;
b = true;
}
}