Merge bitcoin#10099: Slightly Improve Unit Tests for Checkqueue

8c2f4b8 Expose more parallelism with relaxed atomics (suggested in bitcoin#9938). Fix a test to check the exclusive or of two properties rather than just or. (Jeremy Rubin)

Pull request description:

  This PR is in response to bitcoin#10026 and some feedback on bitcoin#9938.

  ~Locally, all the checkqueue tests ran 3.2X faster on my machine. The worst offender, `test_CheckQueue_Correct_Random` ran 3.4X faster.~

  1. ~Removes `GetRand()` and replaces it with a single deterministic FastRandomContext instance.~ bitcoin#10321 replicated this

  1. Exposes more parallelism with relaxed atomics, increasing chance of catching a bug. This does not change performance on my machine.

  1. Makes one test case more restrictive (xor instead of or, see bitcoin#9938).

Tree-SHA512: a59dfbee0273c713525a130dfedc1c7ff26f50c2aaca1e94ef5d759b1d6ea6338ffbd97f863b9f6209750d8a788a15fa8ae1bf26774ed2473c520811337e6b00

Author: sipa

src/test/checkqueue_tests.cpp

@@ -38,7 +38,7 @@ struct FakeCheckCheckCompletion {
     static std::atomic<size_t> n_calls;
     bool operator()()
     {
-        ++n_calls;
+        n_calls.fetch_add(1, std::memory_order_relaxed);
         return true;
     }
     void swap(FakeCheckCheckCompletion& x){};
@@ -88,15 +88,15 @@ struct MemoryCheck {
         //
         // Really, copy constructor should be deletable, but CCheckQueue breaks
         // if it is deleted because of internal push_back.
-        fake_allocated_memory += b;
+        fake_allocated_memory.fetch_add(b, std::memory_order_relaxed);
     };
     MemoryCheck(bool b_) : b(b_)
     {
-        fake_allocated_memory += b;
+        fake_allocated_memory.fetch_add(b, std::memory_order_relaxed);
     };
-    ~MemoryCheck(){
-        fake_allocated_memory -= b;
-    
+    ~MemoryCheck()
+    {
+        fake_allocated_memory.fetch_sub(b, std::memory_order_relaxed);
     };
     void swap(MemoryCheck& x) { std::swap(b, x.b); };
 };
@@ -117,9 +117,9 @@ struct FrozenCleanupCheck {
     {
         if (should_freeze) {
             std::unique_lock<std::mutex> l(m);
-            nFrozen = 1;
+            nFrozen.store(1, std::memory_order_relaxed);
             cv.notify_one();
-            cv.wait(l, []{ return nFrozen == 0;});
+            cv.wait(l, []{ return nFrozen.load(std::memory_order_relaxed) == 0;});
         }
     }
     void swap(FrozenCleanupCheck& x){std::swap(should_freeze, x.should_freeze);};
@@ -262,7 +262,7 @@ BOOST_AUTO_TEST_CASE(test_CheckQueue_Recovers_From_Failure)
                 control.Add(vChecks);
             }
             bool r =control.Wait();
-            BOOST_REQUIRE(r || end_fails);
+            BOOST_REQUIRE(r != end_fails);
         }
     }
     tg.interrupt_all();
@@ -337,7 +337,7 @@ BOOST_AUTO_TEST_CASE(test_CheckQueue_Memory)
     tg.join_all();
 }
 
-// Test that a new verification cannot occur until all checks 
+// Test that a new verification cannot occur until all checks
 // have been destructed
 BOOST_AUTO_TEST_CASE(test_CheckQueue_FrozenCleanup)
 {
@@ -361,11 +361,14 @@ BOOST_AUTO_TEST_CASE(test_CheckQueue_FrozenCleanup)
         std::unique_lock<std::mutex> l(FrozenCleanupCheck::m);
         // Wait until the queue has finished all jobs and frozen
         FrozenCleanupCheck::cv.wait(l, [](){return FrozenCleanupCheck::nFrozen == 1;});
-        // Try to get control of the queue a bunch of times
-        for (auto x = 0; x < 100 && !fails; ++x) {
-            fails = queue->ControlMutex.try_lock();
-        }
-        // Unfreeze
+    }
+    // Try to get control of the queue a bunch of times
+    for (auto x = 0; x < 100 && !fails; ++x) {
+        fails = queue->ControlMutex.try_lock();
+    }
+    {
+        // Unfreeze (we need lock n case of spurious wakeup)
+        std::unique_lock<std::mutex> l(FrozenCleanupCheck::m);
         FrozenCleanupCheck::nFrozen = 0;
     }
     // Awaken frozen destructor