Do not bench spawning the LRU thread

Author: Veykril

Diff for: benches/compare.rs

@@ -3,7 +3,7 @@ use std::mem::transmute;
 use codspeed_criterion_compat::{
     criterion_group, criterion_main, BatchSize, BenchmarkId, Criterion,
 };
-use salsa::Setter;
+use salsa::{Database, Setter};
 
 #[salsa::input]
 pub struct Input {
@@ -34,13 +34,16 @@ fn mutating_inputs(c: &mut Criterion) {
         group.bench_function(BenchmarkId::new("mutating", n), |b| {
             b.iter_batched_ref(
                 || {
-                    let db = salsa::DatabaseImpl::default();
+                    let mut db = salsa::DatabaseImpl::default();
                     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();
 
+                    // spawn the LRU thread
+                    db.synthetic_write(salsa::Durability::HIGH);
+
                     let input = Input::new(&db, base_string.clone());
                     let actual_len = length(&db, input);
                     assert_eq!(base_len, actual_len);

Diff for: benches/incremental.rs

@@ -1,5 +1,5 @@
 use codspeed_criterion_compat::{criterion_group, criterion_main, BatchSize, Criterion};
-use salsa::Setter;
+use salsa::{Database, Setter};
 
 #[salsa::input]
 struct Input {
@@ -26,7 +26,9 @@ fn many_tracked_structs(criterion: &mut Criterion) {
     criterion.bench_function("many_tracked_structs", |b| {
         b.iter_batched_ref(
             || {
-                let db = salsa::DatabaseImpl::new();
+                let mut db = salsa::DatabaseImpl::new();
+                // spawn the LRU thread
+                db.synthetic_write(salsa::Durability::HIGH);
 
                 let input = Input::new(&db, 1_000);
                 let input2 = Input::new(&db, 1);