1 files changed, 57 insertions, 0 deletions
diff --git a/tensorflow/core/util/work_sharder_test.cc b/tensorflow/core/util/work_sharder_test.cc
new file mode 100644
index 0000000000..d9792c0e8d
--- /dev/null
+++ b/tensorflow/core/util/work_sharder_test.cc
@@ -0,0 +1,57 @@
+#include "tensorflow/core/util/work_sharder.h"
+
+#include "tensorflow/core/platform/logging.h"
+#include "tensorflow/core/lib/core/threadpool.h"
+#include "tensorflow/core/platform/port.h"
+#include "tensorflow/core/platform/test_benchmark.h"
+#include <gtest/gtest.h>
+
+namespace tensorflow {
+namespace {
+
+void RunSharding(int64 num_workers, int64 total, int64 cost_per_unit) {
+  thread::ThreadPool threads(Env::Default(), "test", 16);
+  mutex mu;
+  int64 num_shards = 0;
+  int64 num_done_work = 0;
+  std::vector<bool> work(total, false);
+  Shard(num_workers, &threads, total, cost_per_unit,
+        [&mu, &num_shards, &num_done_work, &work](int start, int limit) {
+          VLOG(1) << "Shard [" << start << "," << limit << ")";
+          mutex_lock l(mu);
+          ++num_shards;
+          for (; start < limit; ++start) {
+            EXPECT_FALSE(work[start]);  // No duplicate
+            ++num_done_work;
+            work[start] = true;
+          }
+        });
+  EXPECT_LE(num_shards, num_workers + 1);
+  EXPECT_EQ(num_done_work, total);
+  LOG(INFO) << num_workers << " " << total << " " << cost_per_unit << " "
+            << num_shards;
+}
+
+TEST(Shard, Basic) {
+  for (auto workers : {0, 1, 2, 3, 5, 7, 10, 11, 15, 100, 1000}) {
+    for (auto total : {0, 1, 7, 10, 64, 100, 256, 1000, 9999}) {
+      for (auto cost_per_unit : {0, 1, 11, 102, 1003, 10005, 1000007}) {
+        RunSharding(workers, total, cost_per_unit);
+      }
+    }
+  }
+}
+
+void BM_Sharding(int iters, int arg) {
+  thread::ThreadPool threads(Env::Default(), "test", 16);
+  const int64 total = 1LL << 30;
+  auto lambda = [](int64 start, int64 limit) {};
+  auto work = std::cref(lambda);
+  for (; iters > 0; iters -= arg) {
+    Shard(arg - 1, &threads, total, 1, work);
+  }
+}
+BENCHMARK(BM_Sharding)->Range(1, 128);
+
+}  // namespace
+}  // namespace tensorflow