fix: switch to walltime mode

Author: greged93

.github/workflows/bench.yml

@@ -13,7 +13,7 @@ env:
 name: bench
 jobs:
   codspeed:
-    runs-on: ubuntu-latest
+    runs-on: codspeed-macro
     steps:
       - uses: actions/checkout@v5
       - uses: rui314/setup-mold@v1
@@ -30,4 +30,5 @@ jobs:
       - name: Run the benchmarks
         uses: CodSpeedHQ/action@v3
         with:
+          mode: walltime
           run: cargo codspeed run --workspace