Merge pull request #643 from Veykril/veykril/push-xkzvyxqwxurm

Fix compare benchmarks not benching the right things

benches/compare.rs

@@ -1,4 +1,8 @@
-use codspeed_criterion_compat::{criterion_group, criterion_main, BenchmarkId, Criterion};
+use std::mem::transmute;
+
+use codspeed_criterion_compat::{
+    criterion_group, criterion_main, BatchSize, BenchmarkId, Criterion,
+};
 use salsa::Setter;
 
 #[salsa::input]
@@ -26,25 +30,30 @@ fn mutating_inputs(c: &mut Criterion) {
         codspeed_criterion_compat::measurement::WallTime,
     > = c.benchmark_group("Mutating Inputs");
 
-    let mut db = salsa::DatabaseImpl::default();
-
     for n in &[10, 20, 30] {
-        let base_string = "hello, world!".to_owned();
-        let base_len = base_string.len();
-
-        let string = base_string.clone().repeat(*n);
-        let new_len = string.len();
-
         group.bench_function(BenchmarkId::new("mutating", n), |b| {
-            b.iter(|| {
+            b.iter_batched_ref(
-                let input = Input::new(&db, base_string.clone());
+                || {
-                let actual_len = length(&db, input);
+                    let db = salsa::DatabaseImpl::default();
-                assert_eq!(base_len, actual_len);
+                    let base_string = "hello, world!".to_owned();
+                    let base_len = base_string.len();
 
-                input.set_text(&mut db).to(string.clone());
+                    let string = base_string.clone().repeat(*n);
-                let actual_len = length(&db, input);
+                    let new_len = string.len();
-                assert_eq!(new_len, actual_len);
+
-            })
+                    let input = Input::new(&db, base_string.clone());
+                    let actual_len = length(&db, input);
+                    assert_eq!(base_len, actual_len);
+
+                    (db, input, string, new_len)
+                },
+                |&mut (ref mut db, input, ref string, new_len)| {
+                    input.set_text(db).to(string.clone());
+                    let actual_len = length(db, input);
+                    assert_eq!(new_len, actual_len);
+                },
+                BatchSize::SmallInput,
+            )
         });
     }
 
@@ -56,34 +65,58 @@ fn inputs(c: &mut Criterion) {
         codspeed_criterion_compat::measurement::WallTime,
     > = c.benchmark_group("Mutating Inputs");
 
-    let db = salsa::DatabaseImpl::default();
-
     group.bench_function(BenchmarkId::new("new", "InternedInput"), |b| {
-        b.iter(|| {
+        b.iter_batched_ref(
-            let input: InternedInput = InternedInput::new(&db, "hello, world!".to_owned());
+            salsa::DatabaseImpl::default,
-            interned_length(&db, input);
+            |db| {
-        })
+                let input: InternedInput = InternedInput::new(db, "hello, world!".to_owned());
+                interned_length(db, input);
+            },
+            BatchSize::SmallInput,
+        )
     });
 
     group.bench_function(BenchmarkId::new("amortized", "InternedInput"), |b| {
-        let input = InternedInput::new(&db, "hello, world!".to_owned());
+        b.iter_batched_ref(
-        let _ = interned_length(&db, input);
+            || {
-
+                let db = salsa::DatabaseImpl::default();
-        b.iter(|| interned_length(&db, input));
+                // we can't pass this along otherwise, and the lifetime is generally informational
+                let input: InternedInput<'static> =
+                    unsafe { transmute(InternedInput::new(&db, "hello, world!".to_owned())) };
+                let _ = interned_length(&db, input);
+                (db, input)
+            },
+            |&mut (ref db, input)| {
+                interned_length(db, input);
+            },
+            BatchSize::SmallInput,
+        )
     });
 
     group.bench_function(BenchmarkId::new("new", "Input"), |b| {
-        b.iter(|| {
+        b.iter_batched_ref(
-            let input = Input::new(&db, "hello, world!".to_owned());
+            salsa::DatabaseImpl::default,
-            length(&db, input);
+            |db| {
-        })
+                let input = Input::new(db, "hello, world!".to_owned());
+                length(db, input);
+            },
+            BatchSize::SmallInput,
+        )
     });
 
     group.bench_function(BenchmarkId::new("amortized", "Input"), |b| {
-        let input = Input::new(&db, "hello, world!".to_owned());
+        b.iter_batched_ref(
-        let _ = length(&db, input);
+            || {
-
+                let db = salsa::DatabaseImpl::default();
-        b.iter(|| length(&db, input));
+                let input = Input::new(&db, "hello, world!".to_owned());
+                let _ = length(&db, input);
+                (db, input)
+            },
+            |&mut (ref db, input)| {
+                length(db, input);
+            },
+            BatchSize::SmallInput,
+        )
     });
 
     group.finish();