| 1 | //===-- thread_contention.cpp -----------------------------------*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "gwp_asan/tests/harness.h" |
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| 10 | |
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| 11 | // Note: Compilation of <atomic> and <thread> are extremely expensive for |
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| 12 | // non-opt builds of clang. |
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| 13 | #include <atomic> |
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| 14 | #include <cstdlib> |
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| 15 | #include <thread> |
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| 16 | #include <vector> |
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| 17 | |
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| 18 | void asyncTask(gwp_asan::GuardedPoolAllocator *GPA, |
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| 19 | std::atomic<bool> *StartingGun, unsigned NumIterations) { |
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| 20 | while (!*StartingGun) { |
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| 21 | // Wait for starting gun. |
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| 22 | } |
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| 23 | |
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| 24 | // Get ourselves a new allocation. |
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| 25 | for (unsigned i = 0; i < NumIterations; ++i) { |
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| 26 | volatile char *Ptr = reinterpret_cast<volatile char *>( |
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| 27 | GPA->allocate(Size: GPA->getAllocatorState()->maximumAllocationSize())); |
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| 28 | // Do any other threads have access to this page? |
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| 29 | EXPECT_EQ(*Ptr, 0); |
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| 30 | |
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| 31 | // Mark the page as from malloc. Wait to see if another thread also takes |
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| 32 | // this page. |
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| 33 | *Ptr = 'A'; |
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| 34 | std::this_thread::sleep_for(std::chrono::nanoseconds(10000)); |
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| 35 | |
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| 36 | // Check we still own the page. |
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| 37 | EXPECT_EQ(*Ptr, 'A'); |
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| 38 | |
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| 39 | // And now release it. |
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| 40 | *Ptr = 0; |
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| 41 | GPA->deallocate(Ptr: const_cast<char *>(Ptr)); |
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| 42 | } |
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| 43 | } |
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| 44 | |
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| 45 | void runThreadContentionTest(unsigned NumThreads, unsigned NumIterations, |
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| 46 | gwp_asan::GuardedPoolAllocator *GPA) { |
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| 47 | std::atomic<bool> StartingGun{false}; |
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| 48 | std::vector<std::thread> Threads; |
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| 49 | |
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| 50 | for (unsigned i = 0; i < NumThreads; ++i) { |
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| 51 | Threads.emplace_back(asyncTask, GPA, &StartingGun, NumIterations); |
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| 52 | } |
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| 53 | |
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| 54 | StartingGun = true; |
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| 55 | |
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| 56 | for (auto &T : Threads) |
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| 57 | T.join(); |
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| 58 | } |
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| 59 | |
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| 60 | TEST_F(CustomGuardedPoolAllocator, ThreadContention) { |
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| 61 | unsigned NumThreads = 4; |
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| 62 | unsigned NumIterations = 10000; |
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| 63 | InitNumSlots(NumThreads); |
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| 64 | runThreadContentionTest(NumThreads, NumIterations, &GPA); |
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| 65 | } |
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| 66 | |
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