Added bench for equality.

rust/arrow/Cargo.toml

@@ -112,3 +112,7 @@ harness = false
 [[bench]]
 name = "csv_writer"
 harness = false
+
+[[bench]]
+name = "equal"
+harness = false

rust/arrow/benches/equal.rs

@@ -0,0 +1,93 @@
+// 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.
+
+#[macro_use]
+extern crate criterion;
+use criterion::Criterion;
+
+use rand::distributions::Alphanumeric;
+use rand::Rng;
+use std::sync::Arc;
+
+extern crate arrow;
+
+use arrow::array::*;
+
+fn create_string_array(size: usize, with_nulls: bool) -> ArrayRef {
+    // use random numbers to avoid spurious compiler optimizations wrt to branching
+    let mut rng = rand::thread_rng();
+    let mut builder = StringBuilder::new(size);
+
+    for _ in 0..size {
+        if with_nulls && rng.gen::<f32>() > 0.5 {
+            builder.append_null().unwrap();
+        } else {
+            let string = rand::thread_rng()
+                .sample_iter(&Alphanumeric)
+                .take(10)
+                .collect::<String>();
+            builder.append_value(&string).unwrap();
+        }
+    }
+    Arc::new(builder.finish())
+}
+
+fn create_array(size: usize, with_nulls: bool) -> ArrayRef {
+    // use random numbers to avoid spurious compiler optimizations wrt to branching
+    let mut rng = rand::thread_rng();
+    let mut builder = Float32Builder::new(size);
+
+    for _ in 0..size {
+        if with_nulls && rng.gen::<f32>() > 0.5 {
+            builder.append_null().unwrap();
+        } else {
+            builder.append_value(rng.gen()).unwrap();
+        }
+    }
+    Arc::new(builder.finish())
+}
+
+fn bench_equal(arr_a: &ArrayRef) {
+    let arr_a = arr_a.as_any().downcast_ref::<Float32Array>().unwrap();
+    criterion::black_box(arr_a.equals(arr_a));
+}
+
+fn bench_equal_string(arr_a: &ArrayRef) {
+    let arr_a = arr_a.as_any().downcast_ref::<StringArray>().unwrap();
+    criterion::black_box(arr_a.equals(arr_a));
+}
+
+fn add_benchmark(c: &mut Criterion) {
+    let arr_a = create_array(512, false);
+    c.bench_function("equal_512", |b| b.iter(|| bench_equal(&arr_a)));
+
+    let arr_a_nulls = create_array(512, true);
+    c.bench_function("equal_nulls_512", |b| b.iter(|| bench_equal(&arr_a_nulls)));
+
+    let arr_a = create_string_array(512, false);
+    c.bench_function("equal_string_512", |b| {
+        b.iter(|| bench_equal_string(&arr_a))
+    });
+
+    let arr_a_nulls = create_string_array(512, true);
+    c.bench_function("equal_string_nulls_512", |b| {
+        b.iter(|| bench_equal_string(&arr_a_nulls))
+    });
+}
+
+criterion_group!(benches, add_benchmark);
+criterion_main!(benches);