Microbenchmarks for ludicrous mode

Cargo.toml

@@ -12,6 +12,10 @@ categories = ["email", "parser-implementations"]
 readme = "README.md"
 resolver = "2"
 
+[[bench]]
+name = "bench"
+harness = false
+
 [dependencies]
 encoding_rs = { version="0.8", optional=true }
 serde = { version = "1.0", features = ["derive"], optional=true }
@@ -22,12 +26,11 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 bincode = "1.3.3"
 chrono = "0.4"
+criterion = "0.5"
+rand = "0.8.5"
 
 [features]
 default = ["full_encoding"]
 full_encoding = ["encoding_rs"]
 serde_support = ["serde"]
 ludicrous_mode = []
-
-[profile.bench]
-debug = true

benches/bench.rs

@@ -0,0 +1,8 @@
+use criterion::{criterion_group, criterion_main};
+
+mod ludicrous;
+mod parse;
+
+// run benchmarks with: cargo bench --bench bench
+criterion_group!(benches, ludicrous::ludicrous_bench, parse::parse_bench);
+criterion_main!(benches);

benches/ludicrous.rs

@@ -0,0 +1,50 @@
+use criterion::{BatchSize, Bencher, black_box, Criterion};
+use rand::Rng;
+use rand::rngs::OsRng;
+
+
+static HDR_HASH: &[u8] = &[
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 0, 20, 5, 0, 0, 25, 0, 5, 20, 73, 25, 25, 30, 10, 10, 5, 73, 0, 0, 15, 73, 73, 73, 73, 20,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+    73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73, 73,
+];
+
+/// Confirm whether ludicrous mode makes an impact.
+pub fn ludicrous_bench(c: &mut Criterion) {
+    let mut group = c.benchmark_group("ludicrous");
+    group.sample_size(10);
+    group.bench_function("with", bench_with);
+    group.bench_function("without", bench_without);
+}
+
+/// With unsafe ludicrous mode code.
+fn bench_with(b: &mut Bencher) {
+    b.iter_batched(|| {
+        OsRng.gen()
+    }, |rand: u8| {
+        black_box({
+            unsafe {
+                *HDR_HASH.get_unchecked(rand as usize)
+            }
+        })
+    }, BatchSize::SmallInput);
+}
+
+/// Fully safe code.
+fn bench_without(b: &mut Bencher) {
+    b.iter_batched(|| {
+        OsRng.gen()
+    }, |rand: u8| {
+        black_box({
+            HDR_HASH[rand as usize]
+        })
+    }, BatchSize::SmallInput);
+}

benches/parse.rs

@@ -0,0 +1,58 @@
+use criterion::{BatchSize, Bencher, black_box, Criterion};
+use mail_parser::MessageParser;
+
+const INPUT: &[u8] = br#"From: Art Vandelay <[email protected]> (Vandelay Industries)
+To: "Colleagues": "James Smythe" <[email protected]>; Friends:
+    [email protected], =?UTF-8?Q?John_Sm=C3=AEth?= <[email protected]>;
+Date: Sat, 20 Nov 2021 14:22:01 -0800
+Subject: Why not both importing AND exporting? =?utf-8?b?4pi6?=
+Content-Type: multipart/mixed; boundary="festivus";
+
+--festivus
+Content-Type: text/html; charset="us-ascii"
+Content-Transfer-Encoding: base64
+
+PGh0bWw+PHA+SSB3YXMgdGhpbmtpbmcgYWJvdXQgcXVpdHRpbmcgdGhlICZsZHF1bztle
+HBvcnRpbmcmcmRxdW87IHRvIGZvY3VzIGp1c3Qgb24gdGhlICZsZHF1bztpbXBvcnRpbm
+cmcmRxdW87LDwvcD48cD5idXQgdGhlbiBJIHRob3VnaHQsIHdoeSBub3QgZG8gYm90aD8
+gJiN4MjYzQTs8L3A+PC9odG1sPg==
+--festivus
+Content-Type: message/rfc822
+
+From: "Cosmo Kramer" <[email protected]>
+Subject: Exporting my book about coffee tables
+Content-Type: multipart/mixed; boundary="giddyup";
+
+--giddyup
+Content-Type: text/plain; charset="utf-16"
+Content-Transfer-Encoding: quoted-printable
+
+=FF=FE=0C!5=D8"=DD5=D8)=DD5=D8-=DD =005=D8*=DD5=D8"=DD =005=D8"=
+=DD5=D85=DD5=D8-=DD5=D8,=DD5=D8/=DD5=D81=DD =005=D8*=DD5=D86=DD =
+=005=D8=1F=DD5=D8,=DD5=D8,=DD5=D8(=DD =005=D8-=DD5=D8)=DD5=D8"=
+=DD5=D8=1E=DD5=D80=DD5=D8"=DD!=00
+--giddyup
+Content-Type: image/gif; name*1="about "; name*0="Book ";
+              name*2*=utf-8''%e2%98%95 tables.gif
+Content-Transfer-Encoding: Base64
+Content-Disposition: attachment
+
+R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
+--giddyup--
+--festivus--
+"#;
+
+
+pub fn parse_bench(c: &mut Criterion) {
+    let mut group = c.benchmark_group("parse");
+    group.sample_size(10);
+    group.bench_function("constant", bench_with);
+}
+
+fn bench_with(b: &mut Bencher) {
+    b.iter(|| {
+        black_box({
+            MessageParser::default().parse(INPUT).unwrap()
+        })
+    });
+}