fix: ci and small refactoring

Author: remimimimimi

.github/workflows/benchmark.yml

@@ -31,10 +31,11 @@ jobs:
           bins: cargo-codspeed
 
       - name: Build the benchmark target(s)
-        run: cd crates/pixi_bench && cargo codspeed build && cd ../../
+        run: cargo codspeed build -p pixi_bench
 
       - name: Run the benchmarks
-        uses: CodSpeedHQ/action@v3
+        uses: CodSpeedHQ/action@v4
         with:
-          run: cd crates/pixi_bench && cargo codspeed run && cd ../../
+          run: cargo codspeed run -p pixi_bench
+          mode: "instrumentation"
           token: ${{ secrets.CODSPEED_TOKEN }}

crates/pixi_bench/benches/cold_warm_install.rs

@@ -298,11 +298,9 @@ platforms = ["linux-64", "osx-64", "osx-arm64", "win-64"]
         packages: &[&str],
     ) -> Result<Duration, Box<dyn std::error::Error>> {
         let mut cmd = Command::new("pixi");
-        cmd.arg("install").current_dir(&self.project_dir);
-
-        for (key, value) in self.get_env_vars() {
-            cmd.env(key, value);
-        }
+        cmd.arg("install")
+            .current_dir(&self.project_dir)
+            .envs(&self.get_env_vars());
 
         println!("⏱️ Timing: pixi install {} packages", packages.len());