Add a benchmark for for `unmultiply_inplace` in `pixels` (#33584)

* bench unmultiply_inplace

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

* create data in one line

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

* number_of_pixels

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

---------

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

2 files changed, 38 insertions, 0 deletions

diff --git a/components/pixels/Cargo.toml b/components/pixels/Cargo.toml
index 595c4861008..4d5b16ab9a4 100644
--- a/components/pixels/Cargo.toml
+++ b/components/pixels/Cargo.toml
@@ -20,3 +20,11 @@ malloc_size_of_derive = { workspace = true }
 log = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 webrender_api = { workspace = true }
+
+[dev-dependencies]
+criterion = { version = "0.5", features = ["html_reports"] }
+
+[[bench]]
+name = "benches"
+path = "benches.rs"
+harness = false
diff --git a/components/pixels/benches.rs b/components/pixels/benches.rs
new file mode 100644
index 00000000000..50002851d45
--- /dev/null
+++ b/components/pixels/benches.rs
@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use criterion::*;
+
+fn create_data(number_of_pixels: usize) -> Vec<u8> {
+    (0..=number_of_pixels)
+        .map(|i| {
+            let i = (i % 255) as u8;
+            [i, i, i, i]
+        })
+        .flatten()
+        .collect()
+}
+
+fn bench(c: &mut Criterion) {
+    let data = create_data(1_000_000);
+
+    c.bench_function("unmultiply_inplace", move |b| {
+        b.iter_batched(
+            || data.clone(),
+            |mut data| pixels::unmultiply_inplace(&mut data),
+            BatchSize::SmallInput,
+        )
+    });
+}
+
+criterion_group!(benches, bench);
+criterion_main!(benches);