Refactors Rcu test case

diff --git a/folly/stress-test/stress-parallel-folly-sync.cpp b/folly/stress-test/stress-parallel-folly-sync.cpp
index c1b6ed573e31171dfe4ea4e1914c472cfca7ea13..4cb37b473506fe021fed0d30716359adf44ed0be 100644 (file)
--- a/folly/stress-test/stress-parallel-folly-sync.cpp
+++ b/folly/stress-test/stress-parallel-folly-sync.cpp
@@ -8,10 +8,13 @@ protected:
   // Simulate as the data protected by the lock.
   static size_t locked_data;
   static std::atomic<RcuData*> rcu_data;
-  // For RCU, we mostly want to benchmark the readers (cause it's designed for
-  // very fast readers and occasional writers). We have a writer thread that
-  // runs nonstop until all other reader threads are done.
+  // For RCU, we want to benchmark two things:
+  // (1) Readers --- we have a writer thread that runs nonstop until all other
+  // reader threads are done with a certain number of reads.
+  // (2) Writers --- we have several reader threads that run nonstop until a
+  // writer thread finishes a certain number of writes.
   static std::atomic_uint rcu_readers_num;
+  static std::atomic_uint rcu_writers_num;
   // MicroLock
   static size_t s_nMicroLockPassCount;
   // MicroSpinLock
@@ -43,9 +46,9 @@ protected:
     GetConfigNonZeroExpected(RWSpinLockPassCount, 5000000);
     GetConfigNonZeroExpected(RWTicketSpinLockPassCount, 5000000);
     GetConfigNonZeroExpected(RcuReaderPassCount, 10000);
-    GetConfigNonZeroExpected(RcuWriterPassCount, 500);
     // Every 100 ms by default there will be a writer.
     GetConfigNonZeroExpected(RcuWriterFrequency, 100);
+    GetConfigNonZeroExpected(RcuWriterPassCount, 500);
 
     GetConfigNonZeroExpected(SharedMutexWritePercentage, 5);
     GetConfigNonZeroExpected(RWSpinLockWritePercentage, 5);
@@ -54,34 +57,42 @@ protected:
     rcu_data.store(new RcuData(), std::memory_order_relaxed);
   }
 
-  static void run_rcu_writer_sync() {
+  static void rcu_write_sync() {
+    auto *old_data = rcu_data.load(std::memory_order_consume);
+    auto *new_data = new RcuData(*old_data);
+    new_data->d1++;
+    new_data->d2++;
+    rcu_data.store(new_data, std::memory_order_release);
+    folly::synchronize_rcu();
+    delete old_data;
+  }
+
+  static void rcu_write_retire() {
+    auto *old_data = rcu_data.load(std::memory_order_consume);
+    auto *new_data = new RcuData(*old_data);
+    new_data->d1++;
+    new_data->d2++;
+    rcu_data.store(new_data, std::memory_order_release);
+    folly::rcu_retire(old_data);
+  }
+
+  static void run_rcu_writer_sync_nonstop(size_t pass_count) {
     while (rcu_readers_num.load(std::memory_order_acquire) > 0) {
-      auto *old_data = rcu_data.load(std::memory_order_consume);
-      auto *new_data = new RcuData(*old_data);
-      new_data->d1++;
-      new_data->d2++;
-      rcu_data.store(new_data, std::memory_order_release);
-      folly::synchronize_rcu();
-      delete old_data;
+      rcu_write_sync();
       std::this_thread::sleep_for(
           std::chrono::milliseconds(s_nRcuWriterFrequency));
     }
   }
 
-  static void run_rcu_writer_no_sync() {
+  static void run_rcu_writer_retire_nonstop(size_t pass_count) {
     while (rcu_readers_num.load(std::memory_order_acquire) > 0) {
-      auto *old_data = rcu_data.load(std::memory_order_consume);
-      auto *new_data = new RcuData(*old_data);
-      new_data->d1++;
-      new_data->d2++;
-      rcu_data.store(new_data, std::memory_order_release);
-      folly::rcu_retire(old_data);
+      rcu_write_retire();
       std::this_thread::sleep_for(
           std::chrono::milliseconds(s_nRcuWriterFrequency));
     }
   }
 
-  static void run_rcu_reader(size_t pass_count) {
+  static void run_rcu_reader_pass_count(size_t pass_count) {
     size_t sum = 0;
     for (size_t count = 0; count < pass_count; count++) {
       folly::rcu_reader g;
@@ -93,6 +104,30 @@ protected:
     EXPECT_GT(sum, 0);
   }
 
+  static void run_rcu_writer_sync_pass_count(size_t pass_count) {
+    for (size_t count = 0; count < pass_count; count++) {
+      rcu_write_sync();
+    }
+    rcu_writers_num.fetch_sub(1, std::memory_order_release);
+  }
+
+  static void run_rcu_writer_retire_pass_count(size_t pass_count) {
+    for (size_t count = 0; count < pass_count; count++) {
+      rcu_write_retire();
+    }
+    rcu_writers_num.fetch_sub(1, std::memory_order_release);
+  }
+
+  static void run_rcu_reader_nonstop(size_t pass_count) {
+    size_t sum = 0;
+    while (rcu_writers_num.load(std::memory_order_acquire) > 0) {
+      folly::rcu_reader g;
+      auto *data = rcu_data.load(std::memory_order_consume);
+      sum += (data->d1 + data->d2);
+    }
+    EXPECT_GT(sum, 0);
+  }
+
   template <typename Lock>
   static void run_rw_lock(Lock *l, size_t pass_count,
                           unsigned write_percentage) {
@@ -131,15 +166,17 @@ protected:
     }
   }
 
-  template <typename WriterFunc>
-  static void FollyRcuThreading(WriterFunc writer_func) {
+  template <typename WriterFunc, typename ReaderFunc>
+  static void FollyRcuThreading(WriterFunc writer_func,
+                                ReaderFunc reader_func) {
     rcu_readers_num.store(s_nThreadCount - 1, std::memory_order_release);
+    rcu_writers_num.store(1, std::memory_order_release);
 
     std::unique_ptr<std::thread[]> threads(new std::thread[s_nThreadCount]);
     // One of the threads is a writer.
-    threads[0] = std::thread(writer_func);
+    threads[0] = std::thread(writer_func, s_nRcuWriterPassCount);
     for (size_t i = 1; i < s_nThreadCount; i++) {
-      threads[i] = std::thread(run_rcu_reader, s_nRcuReaderPassCount);
+      threads[i] = std::thread(reader_func, s_nRcuReaderPassCount);
     }
     for (size_t i = 0; i < s_nThreadCount; i++) {
       threads[i].join();
@@ -167,6 +204,7 @@ protected:
 size_t FollySyncTest_Parallel::locked_data;
 std::atomic<RcuData*> FollySyncTest_Parallel::rcu_data;
 std::atomic_uint FollySyncTest_Parallel::rcu_readers_num;
+std::atomic_uint FollySyncTest_Parallel::rcu_writers_num;
 size_t FollySyncTest_Parallel::s_nThreadCount;
 size_t FollySyncTest_Parallel::s_nMicroLockPassCount;
 size_t FollySyncTest_Parallel::s_nMicroSpinLockPassCount;
@@ -183,12 +221,12 @@ unsigned FollySyncTest_Parallel::s_nSharedMutexWritePercentage;
 unsigned FollySyncTest_Parallel::s_nRWSpinLockWritePercentage;
 unsigned FollySyncTest_Parallel::s_nRWTicketSpinLockWritePercentage;
 
-TEST_F(FollySyncTest_Parallel, FollyRCU_Sync) {
-  FollyRcuThreading(run_rcu_writer_sync);
+TEST_F(FollySyncTest_Parallel, FollyRCU_NonstopReaderSync) {
+  FollyRcuThreading(run_rcu_writer_sync_nonstop, run_rcu_reader_pass_count);
 }
 
-TEST_F(FollySyncTest_Parallel, FollyRCU_NoSync) {
-  FollyRcuThreading(run_rcu_writer_no_sync);
+TEST_F(FollySyncTest_Parallel, FollyRCU_NonstopReaderNoSync) {
+  FollyRcuThreading(run_rcu_writer_retire_nonstop, run_rcu_reader_pass_count);
 }
 
 TEST_F(FollySyncTest_Parallel, FollyRWTicketSpinLock_32) {