Divan benchmarking PoC

Cargo.toml

@@ -34,6 +34,7 @@ features = ["derive"]
 version = "1.0.61"
 
 [dev-dependencies]
+divan = "0.1.4"
 insta = { version = "1.26.0", default-features = false }
 
 [dev-dependencies.quickcheck]
@@ -52,5 +53,9 @@ tracing = ["dep:tracing", "dep:tracing-subscriber", "dep:tracing-flame"]
 name = "bnf"
 harness = false
 
+[[bench]]
+name = "divan"
+harness = false
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 getrandom = { version = "0.2.5", features = ["js"] } # needed for rand

benches/divan.rs

@@ -0,0 +1,102 @@
+fn main() {
+    init_tracing();
+
+    #[cfg(feature = "tracing")]
+    let _span = tracing::span!(tracing::Level::DEBUG, "BENCH EXAMPLES").entered();
+
+    // Run registered benchmarks.
+    divan::main();
+}
+
+#[cfg(feature = "tracing")]
+fn init_tracing() -> impl Drop {
+    use tracing_flame::FlameLayer;
+    use tracing_subscriber::{fmt, prelude::*};
+    let filter_layer = tracing_subscriber::EnvFilter::from_default_env();
+    let fmt_layer = fmt::Layer::default();
+    let (flame_layer, _guard) = FlameLayer::with_file("./tracing.folded").unwrap();
+
+    tracing_subscriber::registry()
+        .with(filter_layer)
+        .with(fmt_layer)
+        .with(flame_layer)
+        .init();
+
+    _guard
+}
+
+#[cfg(not(feature = "tracing"))]
+fn init_tracing() {}
+
+mod examples {
+    #[divan::bench]
+    fn parse_postal(bencher: divan::Bencher) {
+        let input = divan::black_box(include_str!(
+            "../tests/fixtures/postal_address.terminated.input.bnf"
+        ));
+
+        bencher.bench(|| {
+            input.parse::<bnf::Grammar>().unwrap();
+        });
+    }
+
+    #[divan::bench]
+    fn generate_dna(bencher: divan::Bencher) {
+        bencher
+            .with_inputs(|| {
+                let input = "<dna> ::= <base> | <base> <dna>
+            <base> ::= 'A' | 'C' | 'G' | 'T'";
+                let grammar: bnf::Grammar = input.parse().unwrap();
+                grammar
+            })
+            .bench_refs(|grammar| {
+                grammar.generate().unwrap();
+            });
+    }
+
+    #[divan::bench]
+    fn parse_polish_calculator(bencher: divan::Bencher) {
+        let polish_calc_grammar: bnf::Grammar = "<product> ::= <number> | <op> <product> <product>
+            <op> ::= '+' | '-' | '*' | '/'
+            <number> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'
+        "
+        .parse()
+        .unwrap();
+
+        // use pseudo random for consistent metrics
+        use rand::seq::SliceRandom;
+        let mut rng: rand::rngs::StdRng = rand::SeedableRng::seed_from_u64(0);
+        let random_walk_count = 100usize;
+        let mut random_walks: Vec<_> = (0..random_walk_count)
+            .map(|_| polish_calc_grammar.generate_seeded(&mut rng).unwrap())
+            .collect();
+
+        random_walks.shuffle(&mut rng);
+        let mut random_walks = divan::black_box(random_walks.into_iter());
+
+        bencher.bench_local(|| {
+            let input = random_walks.next().unwrap();
+            let _: Vec<_> = polish_calc_grammar.parse_input(&input).collect();
+        });
+    }
+
+    #[divan::bench]
+    fn parse_infinite_nullable_grammar(bencher: divan::Bencher) {
+        use rand::Rng;
+
+        let infinite_grammar: bnf::Grammar = "
+                <a> ::= '' | <b>
+                <b> ::= <a>"
+            .parse()
+            .unwrap();
+
+        let mut rng: rand::rngs::StdRng = rand::SeedableRng::seed_from_u64(0);
+
+        bencher
+            .with_inputs(|| rng.gen_range(1..100))
+            .count_inputs_as::<divan::counter::ItemsCount>()
+            .bench_local_values(|parse_count| {
+                let _: Vec<_> = infinite_grammar.parse_input("").take(parse_count).collect();
+            });
+    }
+}