Profile allocations in benchmarks

This adds `AllocProfiler`, an allocator implementation that tracks the
number of allocations and bytes allocated during benchmarks. It can wrap
any `GlobalAlloc`, such as `mimalloc`.

CHANGELOG.md

@@ -8,6 +8,11 @@ Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Added
+
+- [`AllocProfiler`](https://docs.rs/divan/0.1.6/divan/struct.AllocProfiler.html)
+  allocator that tracks allocation counts and sizes during benchmarks.
+
 ## [0.1.5] - 2023-12-05
 
 ### Added

Cargo.toml

@@ -19,6 +19,9 @@ clap = { version = "4", default-features = false, features = ["std", "env"] }
 condtype = "1.3"
 regex = { package = "regex-lite", version = "0.1", default-features = false, features = ["std", "string"] }
 
+[dev-dependencies]
+mimalloc = "0.1"
+
 [features]
 default = ["wrap_help"]
 help = ["clap/help"]

examples/benches/collections.rs

@@ -6,10 +6,13 @@
 
 use std::collections::{BTreeSet, BinaryHeap, HashSet, LinkedList, VecDeque};
 
-use divan::{black_box, Bencher};
+use divan::{black_box, AllocProfiler, Bencher};
 
 mod util;
 
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
+
 fn main() {
     divan::main();
 }

examples/benches/hash.rs

@@ -5,6 +5,10 @@
 //! ```
 
 use digest::Digest;
+use divan::AllocProfiler;
+
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
 
 fn main() {
     divan::main();

examples/benches/image.rs

@@ -6,9 +6,12 @@
 //! cargo bench -q -p examples --bench image --features image
 //! ```
 
-use divan::{black_box, counter::BytesCount, Bencher};
+use divan::{black_box, counter::BytesCount, AllocProfiler, Bencher};
 use image::{GenericImage, ImageBuffer, Rgba};
 
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
+
 fn main() {
     divan::main();
 }

examples/benches/panic.rs

@@ -6,7 +6,10 @@
 
 use std::panic;
 
-use divan::{black_box, black_box_drop};
+use divan::{black_box, black_box_drop, AllocProfiler};
+
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
 
 fn main() {
     // Silence panics.

examples/benches/search.rs

@@ -3,10 +3,13 @@ use std::{
     hash::BuildHasher,
 };
 
-use divan::{black_box_drop, Bencher};
+use divan::{black_box_drop, AllocProfiler, Bencher};
 use fastrand::Rng;
 use ordsearch::OrderedCollection;
 
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
+
 fn main() {
     divan::Divan::from_args()
         .items_count(

examples/benches/sort.rs

@@ -4,9 +4,12 @@
 //! cargo bench -q -p examples --bench sort
 //! ```
 
-use divan::Bencher;
+use divan::{AllocProfiler, Bencher};
 use rayon::slice::ParallelSliceMut;
 
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
+
 fn main() {
     divan::main();
 }

examples/benches/string.rs

@@ -7,9 +7,12 @@
 use divan::{
     black_box, black_box_drop,
     counter::{BytesCount, CharsCount},
-    Bencher,
+    AllocProfiler, Bencher,
 };
 
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
+
 fn main() {
     divan::main();
 }

examples/benches/threads.rs

@@ -13,7 +13,10 @@ use std::{
     thread::{Thread, ThreadId},
 };
 
-use divan::{black_box, black_box_drop, Bencher};
+use divan::{black_box, black_box_drop, AllocProfiler, Bencher};
+
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
 
 fn main() {
     divan::main();

examples/benches/time.rs

@@ -6,7 +6,10 @@
 
 use std::time::{Instant, SystemTime};
 
-use divan::Bencher;
+use divan::{AllocProfiler, Bencher};
+
+#[global_allocator]
+static ALLOC: AllocProfiler = AllocProfiler::system();
 
 fn main() {
     divan::main();