compiler-rt/lib/gwp_asan/tests/thread_contention.cpp

   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
  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
  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
  60 TEST_F(CustomGuardedPoolAllocator, ThreadContention) {
  61   unsigned NumThreads = 4;
  62   unsigned NumIterations = 10000;
  63   InitNumSlots(NumThreads);
  64   runThreadContentionTest(NumThreads, NumIterations, &GPA);
  65 }