Fix benchmarks on linux

Author: Garmelon

.github/workflows/build-template.yml

@@ -246,7 +246,9 @@ jobs:
           make -C build -j$NPROC check-stage3
         if: matrix.check-stage3
       - name: Test Benchmarks
-        run: nix shell github:Kha/lakeprof -c make -C build -j$NPROC bench
+        run: |
+          cd tests
+          nix develop -c make -C ../build -j$NPROC bench
         if: matrix.test-bench
       - name: Check rebootstrap
         run: |

tests/flake.nix

@@ -0,0 +1,27 @@
+{
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+
+  inputs.lakeprof.url = "github:Kha/lakeprof";
+  inputs.lakeprof.inputs.nixpkgs.follows = "nixpkgs";
+
+  outputs =
+    inputs:
+    let
+      lib = inputs.nixpkgs.lib;
+      forAllSystems = lib.genAttrs lib.systems.flakeExposed;
+    in
+    {
+      devShells = forAllSystems (
+        system:
+        let
+          pkgs = inputs.nixpkgs.legacyPackages.${system};
+          lakeprof = inputs.lakeprof.packages.${system}.default;
+        in
+        {
+          default = pkgs.mkShellNoCC {
+            packages = [ lakeprof ] ++ lib.optional pkgs.stdenv.isLinux pkgs.perf;
+          };
+        }
+      );
+    };
+}