1 files changed, 66 insertions, 0 deletions
diff --git a/third_party/rust/bumpalo/benches/benches.rs b/third_party/rust/bumpalo/benches/benches.rs
new file mode 100644
index 0000000000..5f1415f546
--- /dev/null
+++ b/third_party/rust/bumpalo/benches/benches.rs
@@ -0,0 +1,66 @@
+use criterion::*;
+
+#[derive(Default)]
+struct Small(u8);
+
+#[derive(Default)]
+struct Big([usize; 32]);
+
+fn alloc<T: Default>(n: usize) {
+    let arena = bumpalo::Bump::with_capacity(n * std::mem::size_of::<T>());
+    for _ in 0..n {
+        let arena = black_box(&arena);
+        let val: &mut T = arena.alloc(black_box(Default::default()));
+        black_box(val);
+    }
+}
+
+fn alloc_with<T: Default>(n: usize) {
+    let arena = bumpalo::Bump::with_capacity(n * std::mem::size_of::<T>());
+    for _ in 0..n {
+        let arena = black_box(&arena);
+        let val: &mut T = arena.alloc_with(|| black_box(Default::default()));
+        black_box(val);
+    }
+}
+
+#[cfg(feature = "collections")]
+fn format_realloc(bump: &bumpalo::Bump, n: usize) {
+    let n = criterion::black_box(n);
+    let s = bumpalo::format!(in bump, "Hello {:.*}", n, "World! ");
+    criterion::black_box(s);
+}
+
+const ALLOCATIONS: usize = 10_000;
+
+fn bench_alloc(c: &mut Criterion) {
+    let mut group = c.benchmark_group("alloc");
+    group.throughput(Throughput::Elements(ALLOCATIONS as u64));
+    group.bench_function("small", |b| b.iter(|| alloc::<Small>(ALLOCATIONS)));
+    group.bench_function("big", |b| b.iter(|| alloc::<Big>(ALLOCATIONS)));
+}
+
+fn bench_alloc_with(c: &mut Criterion) {
+    let mut group = c.benchmark_group("alloc-with");
+    group.throughput(Throughput::Elements(ALLOCATIONS as u64));
+    group.bench_function("small", |b| b.iter(|| alloc_with::<Small>(ALLOCATIONS)));
+    group.bench_function("big", |b| b.iter(|| alloc_with::<Big>(ALLOCATIONS)));
+}
+
+fn bench_format_realloc(c: &mut Criterion) {
+    let mut group = c.benchmark_group("format-realloc");
+
+    for n in (1..5).map(|n| n * n * n * 10) {
+        group.throughput(Throughput::Elements(n as u64));
+        group.bench_with_input(BenchmarkId::new("format-realloc", n), &n, |b, n| {
+            let mut bump = bumpalo::Bump::new();
+            b.iter(|| {
+                bump.reset();
+                format_realloc(&bump, *n);
+            });
+        });
+    }
+}
+
+criterion_group!(benches, bench_alloc, bench_alloc_with, bench_format_realloc);
+criterion_main!(benches);