PARQUET-600: Add benchmarks for RLE-Level encoding

Author: Uwe L. Korn <uwelk@xhochy.com>

Closes apache#95 from xhochy/parquet-600 and squashes the following commits:

87882fd [Uwe L. Korn] Use MaxBufferSize for size estimation
0fd2a34 [Uwe L. Korn] PARQUET-600: Add benchmarks for RLE-Level encoding

Change-Id: I9fa9bf6bb5f08ac760b5cf6c9f65b797c8bb7444

cpp/src/parquet/column/CMakeLists.txt

@@ -32,3 +32,4 @@ ADD_PARQUET_TEST(properties-test)
 ADD_PARQUET_TEST(scanner-test)
 
 ADD_PARQUET_BENCHMARK(column-io-benchmark)
+ADD_PARQUET_BENCHMARK(level-benchmark)

cpp/src/parquet/column/level-benchmark.cc

@@ -0,0 +1,69 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "benchmark/benchmark.h"
+
+#include "parquet/column/levels.h"
+#include "parquet/util/buffer.h"
+
+namespace parquet {
+
+namespace benchmark {
+
+static void BM_RleEncoding(::benchmark::State& state) {
+  // TODO: More than just all 0s
+  std::vector<int16_t> levels(state.range_x(), 0);
+  int16_t max_level = 1;
+  int64_t rle_size = LevelEncoder::MaxBufferSize(Encoding::RLE, max_level, levels.size());
+  auto buffer_rle = std::make_shared<OwnedMutableBuffer>(rle_size);
+
+  while (state.KeepRunning()) {
+    LevelEncoder level_encoder;
+    level_encoder.Init(Encoding::RLE, max_level, levels.size(),
+        buffer_rle->mutable_data(), buffer_rle->size());
+    level_encoder.Encode(levels.size(), levels.data());
+  }
+  state.SetBytesProcessed(state.iterations() * state.range_x() * sizeof(int16_t));
+}
+
+BENCHMARK(BM_RleEncoding)->Range(1024, 65536);
+
+static void BM_RleDecoding(::benchmark::State& state) {
+  LevelEncoder level_encoder;
+  // TODO: More than just all 0s
+  std::vector<int16_t> levels(state.range_x(), 0);
+  int16_t max_level = 1;
+  int64_t rle_size = LevelEncoder::MaxBufferSize(Encoding::RLE, max_level, levels.size());
+  auto buffer_rle = std::make_shared<OwnedMutableBuffer>(rle_size);
+  level_encoder.Init(Encoding::RLE, max_level, levels.size(), buffer_rle->mutable_data(),
+      buffer_rle->size());
+  level_encoder.Encode(levels.size(), levels.data());
+
+  while (state.KeepRunning()) {
+    LevelDecoder level_decoder;
+    level_decoder.SetData(Encoding::RLE, max_level, levels.size(), buffer_rle->data());
+    level_decoder.Decode(state.range_x(), levels.data());
+  }
+
+  state.SetBytesProcessed(state.iterations() * state.range_x() * sizeof(int16_t));
+}
+
+BENCHMARK(BM_RleDecoding)->Range(1024, 65536);
+
+}  // namespace benchmark
+
+}  // namespace parquet