Alexander Markov
5aead50245
This CL includes db26c89347 (patch set #1)
with fix (patch set #2):
* Include simulator.h explicitly where it is required as it is no
longer included implicitly through other header files.
Original review: https://codereview.chromium.org/2995803002/
When running on the simulator for arm/arm64, compare-and-swap operations
used in VM were synchronized with simulator using mutex.
It heavily impacts performance when doing parallel marking due to high
contention (see #30317).
This synchronization was implemented in order to make simulated
LDREX/STREX instructions aware of CAS performed in VM.
This CL drops this synchronization between VM and simulator:
CAS operations in VM become regular, and simulator remembers value loaded
with load-exclusive and performs CAS when doing store-exclusive to catch
any concurrent modifications.
Speeds up gen_snapshot of flutter benchmark complex_layout from 9.2s
to 8.0s on my MacBook.
R=asiva@google.com
Review-Url: https://codereview.chromium.org/2999853002 .
65 lines
2.0 KiB
C++
65 lines
2.0 KiB
C++
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef RUNTIME_VM_ATOMIC_H_
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#define RUNTIME_VM_ATOMIC_H_
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#include "platform/globals.h"
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#include "vm/allocation.h"
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namespace dart {
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class AtomicOperations : public AllStatic {
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public:
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// Atomically fetch the value at p and increment the value at p.
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// Returns the original value at p.
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static uintptr_t FetchAndIncrement(uintptr_t* p);
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static intptr_t FetchAndIncrement(intptr_t* p);
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// Atomically increment the value at p by 'value'.
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static void IncrementBy(intptr_t* p, intptr_t value);
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static void IncrementInt64By(int64_t* p, int64_t value);
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// Atomically fetch the value at p and decrement the value at p.
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// Returns the original value at p.
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static uintptr_t FetchAndDecrement(uintptr_t* p);
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static intptr_t FetchAndDecrement(intptr_t* p);
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// Atomically decrement the value at p by 'value'.
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static void DecrementBy(intptr_t* p, intptr_t value);
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// Atomically compare *ptr to old_value, and if equal, store new_value.
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// Returns the original value at ptr.
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static uword CompareAndSwapWord(uword* ptr, uword old_value, uword new_value);
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static uint32_t CompareAndSwapUint32(uint32_t* ptr,
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uint32_t old_value,
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uint32_t new_value);
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// Performs a load of a word from 'ptr', but without any guarantees about
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// memory order (i.e., no load barriers/fences).
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template <typename T>
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static T LoadRelaxed(T* ptr) {
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return *static_cast<volatile T*>(ptr);
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}
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};
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} // namespace dart
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#if defined(HOST_OS_ANDROID)
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#include "vm/atomic_android.h"
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#elif defined(HOST_OS_FUCHSIA)
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#include "vm/atomic_fuchsia.h"
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#elif defined(HOST_OS_LINUX)
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#include "vm/atomic_linux.h"
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#elif defined(HOST_OS_MACOS)
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#include "vm/atomic_macos.h"
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#elif defined(HOST_OS_WINDOWS)
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#include "vm/atomic_win.h"
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#else
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#error Unknown target os.
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#endif
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#endif // RUNTIME_VM_ATOMIC_H_
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