Daniel Andersson
17a6b944d1
Thread barrier with:
* fixed (at construction) number n of participating threads {T1,T2,T3,...,Tn}
* unknown number of rounds.
Requirements:
* there is some R such that each participating thread makes
R calls to Sync() followed by its one and only call to Exit().
Guarantees:
* for any two threads Ti and Tj and round number r <= R,
everything done by Ti before its r'th call to Sync() happens before
everything done by Tj after its r'th call to Sync().
Note:
* it's not required that the thread that constructs the barrier participates.
BUG=
Review URL: https://codereview.chromium.org//1337943004 .
60 lines
1.3 KiB
C++
60 lines
1.3 KiB
C++
// Copyright (c) 2015, 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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#include "platform/assert.h"
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#include "vm/random.h"
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#include "vm/thread_barrier.h"
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#include "vm/thread_pool.h"
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#include "vm/unit_test.h"
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namespace dart {
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class FuzzTask : public ThreadPool::Task {
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public:
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FuzzTask(intptr_t num_rounds,
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ThreadBarrier* barrier,
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uint64_t seed)
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: num_rounds_(num_rounds),
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barrier_(barrier),
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rng_(seed) {
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}
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virtual void Run() {
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for (intptr_t i = 0; i < num_rounds_; ++i) {
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RandomSleep();
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barrier_->Sync();
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}
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barrier_->Exit();
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}
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private:
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void RandomSleep() {
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int64_t ms = rng_.NextUInt32() % 4;
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if (ms > 0) {
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OS::Sleep(ms);
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}
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}
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const intptr_t num_rounds_;
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ThreadBarrier* barrier_;
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Random rng_;
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};
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UNIT_TEST_CASE(ThreadBarrier) {
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static const intptr_t kNumTasks = 5;
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static const intptr_t kNumRounds = 500;
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ThreadBarrier barrier(kNumTasks + 1);
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for (intptr_t i = 0; i < kNumTasks; ++i) {
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Dart::thread_pool()->Run(new FuzzTask(kNumRounds, &barrier, i + 1));
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}
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for (intptr_t i = 0; i < kNumRounds; ++i) {
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barrier.Sync();
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}
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barrier.Exit();
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}
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} // namespace dart
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