From 4ada624122d19cd3ec58d9eadb3fd42f3b74c744 Mon Sep 17 00:00:00 2001
From: rmeng <rob.xu.meng@gmail.com>
Date: Wed, 31 May 2023 11:25:06 -0400
Subject: [PATCH] argmin benchmark

---
 rust/Cargo.toml           |  4 +++
 rust/benches/argmin.rs    | 68 +++++++++++++++++++++++++++++++++++++++
 rust/src/utils/testing.rs | 13 +++++++-
 3 files changed, 84 insertions(+), 1 deletion(-)
 create mode 100644 rust/benches/argmin.rs

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 9274298d0c..7b566542a4 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -112,6 +112,10 @@ harness = false
 name = "kmeans"
 harness = false
 
+[[bench]]
+name = "argmin"
+harness = false
+
 [profile.release]
 strip = true
 opt-level = "s"
diff --git a/rust/benches/argmin.rs b/rust/benches/argmin.rs
new file mode 100644
index 0000000000..35f2286b3c
--- /dev/null
+++ b/rust/benches/argmin.rs
@@ -0,0 +1,68 @@
+// Copyright 2023 Lance Developers.
+//
+// Licensed 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.
+
+use std::{sync::Arc, time::Duration};
+
+use arrow_array::{Float32Array, UInt32Array};
+use criterion::{criterion_group, criterion_main, Criterion};
+
+use lance::utils::testing::generate_random_array_with_seed;
+#[cfg(target_os = "linux")]
+use pprof::criterion::{Output, PProfProfiler};
+
+use lance::arrow::argmin;
+
+#[inline]
+fn argmin_arrow(x: &Float32Array) -> u32 {
+    argmin(x).unwrap()
+}
+
+fn argmin_arrow_batch(x: &Float32Array, dimension: usize) -> Arc<UInt32Array> {
+    assert_eq!(x.len() % dimension, 0);
+
+    let idxs = unsafe {
+        UInt32Array::from_trusted_len_iter(
+            (0..x.len())
+                .step_by(dimension)
+                .into_iter()
+                .map(|start| Some(argmin_arrow(&x.slice(start, dimension)))),
+        )
+    };
+    Arc::new(idxs)
+}
+
+fn bench_argmin(c: &mut Criterion) {
+    const DIMENSION: usize = 1024 * 8;
+    const TOTAL: usize = 1024;
+    const SEED: [u8; 32] = [42; 32];
+
+    let target = generate_random_array_with_seed(TOTAL * DIMENSION, SEED);
+
+    c.bench_function("argmin(arrow)", |b| {
+        b.iter(|| {
+            argmin_arrow_batch(&target, DIMENSION);
+        })
+    });
+}
+
+#[cfg(target_os = "linux")]
+criterion_group!(
+    name=benches;
+    config = Criterion::default()
+        .measurement_time(Duration::from_secs(10))
+        .sample_size(32)
+        .with_profiler(PProfProfiler::new(100, Output::Flamegraph(None)));
+    targets = bench_argmin);
+
+criterion_main!(benches);
diff --git a/rust/src/utils/testing.rs b/rust/src/utils/testing.rs
index 982eb5ab3c..68dbfd1e9a 100644
--- a/rust/src/utils/testing.rs
+++ b/rust/src/utils/testing.rs
@@ -17,11 +17,22 @@
 
 //! Testing utilities
 
-use rand::Rng;
+use rand::rngs::StdRng;
+use rand::{Rng, SeedableRng};
 use std::iter::repeat_with;
 
 use arrow_array::Float32Array;
 
+/// Create a random float32 array.
+pub fn generate_random_array_with_seed(n: usize, seed: [u8; 32]) -> Float32Array {
+    let mut rng = StdRng::from_seed(seed);
+    Float32Array::from(
+        repeat_with(|| rng.gen::<f32>())
+            .take(n)
+            .collect::<Vec<f32>>(),
+    )
+}
+
 /// Create a random float32 array.
 pub fn generate_random_array(n: usize) -> Float32Array {
     let mut rng = rand::thread_rng();