Set up codspeed benching

.github/workflows/codspeed.yml

@@ -0,0 +1,40 @@
+name: CodSpeed
+
+on:
+  push:
+    branches:
+      - "main"
+  pull_request:
+  # `workflow_dispatch` allows CodSpeed to trigger backtest
+  # performance analysis in order to generate initial data.
+  workflow_dispatch:
+
+jobs:
+  benchmarks:
+    name: Run benchmarks
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup rust toolchain, cache and cargo-codspeed binary
+        uses: moonrepo/setup-rust@v1
+        with:
+          cache-target: release
+          bins: cargo-codspeed, aoc-cli
+
+      - name: Download available input files
+        env:
+          ADVENT_OF_CODE_SESSION: ${{ secrets.AOC_SESSION }}
+        run: |
+          mkdir -p inputs
+          for i in {1..25}; do
+            aoc download -I -i input/2024/day$i.txt --year 2024 -d $i || true
+          done
+      - name: Build the benchmark target(s)
+        run: cargo codspeed build
+
+      - name: Run the benchmarks
+        uses: CodSpeedHQ/action@v3
+        with:
+          run: cargo codspeed run
+          token: ${{ secrets.CODSPEED_TOKEN }}

Cargo.toml

@@ -17,3 +17,9 @@ tinyvec = "1.8.0"
 
 [dev-dependencies]
 criterion = { version = "2.7.2", package = "codspeed-criterion-compat" }
+indoc = "2.0.5"
+paste = "1.0.15"
+
+[[bench]]
+name = "bench_days"
+harness = false

benches/bench_days.rs

@@ -0,0 +1,41 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use paste::paste;
+
+/// Get input for a single day
+macro_rules! get_day_input {
+    ($day_num:literal) => {
+        include_str!(concat!("../input/2024/day", $day_num, ".txt"))
+    };
+}
+
+/// Define benchmarks for a single day with part1 and part2
+macro_rules! benches_day {
+    ($day_num:literal) => {
+        paste! {
+            use advent_of_code_2024::[<day $day_num>]; // Replace `aoc24` with your crate name
+
+            pub fn [<bench_day $day_num>](c: &mut Criterion) {
+                let mut group = c.benchmark_group(concat!("day", $day_num));
+                let input = get_day_input!($day_num);
+                group.bench_function(format!("day{}_part1", $day_num), |b| b.iter(|| [<day $day_num>]::part1(input)));
+                group.bench_function(format!("day{}_part2", $day_num), |b| b.iter(|| [<day $day_num>]::part2(input)));
+            }
+        }
+    };
+}
+
+/// Create benchmarks for included days
+macro_rules! benches {
+    ($($day_num:literal),*) => {
+        paste! {
+            $(
+                benches_day!($day_num);
+            )*
+
+            criterion_group!(benches, $([<bench_day $day_num>]),*);
+            criterion_main!(benches);
+        }
+    };
+}
+
+benches!(6);