Method ThreadFn

be/src/runtime/io/data-cache-test.cc:282–318

The function is invoked by each thread in the multi-threaded tests below. It inserts chunks of size TEMP_BUFFER_SIZE from different offsets at range [0, 'max_test_offset') from 'test_buffer_'. Afterwards, it tries reading back all the inserted chunks. 'fname_prefix' is the prefix added to the default filename when inserting into the cache. 'max_test_offset' and 'fname_prefix' implicitly control t

  // of cache keys which indirectly control the cache footprint. 'num_misses' records
  // the number of cache misses.
  void ThreadFn(const string& fname_prefix, DataCache* cache, int64_t max_start_offset,
      CountingBarrier* store_barrier, int* num_misses, int64_t* write_time_us) {
    const string& custom_fname = Substitute("$0file", fname_prefix);
    vector<int64_t> offsets;
    for (int64_t offset = 0; offset < max_start_offset; ++offset) {
      offsets.push_back(offset);
    }
    random_shuffle(offsets.begin(), offsets.end());
    int64_t write_start_time = UnixMicros();
    for (int64_t offset : offsets) {
      cache->Store(custom_fname, MTIME, offset, test_buffer() + offset,
          TEMP_BUFFER_SIZE);
    }
    *write_time_us = UnixMicros() - write_start_time;
    // Wait until all threads have finished inserting. Since different threads may be
    // inserting the same cache key and collide, only one thread which wins the race will
    // insert the cache entry. Make sure other threads which lose out on the race will
    // wait for the insertion to complete first before proceeding.
    store_barrier->Notify();
    store_barrier->Wait();

    // Before continue, we should wait for all asynchronous store tasks (if there are)
    // finished.
    WaitForAsyncWrite(*cache);
    for (int64_t offset : offsets) {
      uint8_t buffer[TEMP_BUFFER_SIZE];
      memset(buffer, 0, TEMP_BUFFER_SIZE);
      int64_t bytes_read =
          cache->Lookup(custom_fname, MTIME, offset, TEMP_BUFFER_SIZE, buffer);
      if (bytes_read == TEMP_BUFFER_SIZE) {
        ASSERT_EQ(0, memcmp(buffer, test_buffer() + offset, TEMP_BUFFER_SIZE));
      } else {
        ASSERT_EQ(bytes_read, 0);
        ++(*num_misses);
      }
    }
  }
};

class DataCacheTest :