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