Merge pull request #2398 from the8472/pre-run-command

env var to run a command before every benchmark run

Author: Kobzol

collector/src/bin/collector.rs

@@ -1531,6 +1531,20 @@ async fn run_benchmark_job(
         )));
     }
 
+    // Command launched before a benchmark suite. Useful to run an external root helper
+    // that brings the system in a consistent state.
+    if let Ok(pre_run) = std::env::var("RUSTC_PERF_PRE_RUN_COMMAND") {
+        // split by ascii unit separator
+        let commandline = pre_run.split('\x1f').collect::<Vec<_>>();
+        let mut cmd = tokio::process::Command::new(commandline[0]);
+        cmd.args(&commandline[1..]);
+        cmd.status().await.map_err(|error| {
+            BenchmarkJobError::Permanent(anyhow::anyhow!(
+                "Failed to execute RUSTC_PERF_PRE_RUN_COMMAND `{pre_run}`: {error:?}"
+            ))
+        })?;
+    }
+
     log::info!("Downloading sysroot");
     let toolchain = match &artifact_id {
         ArtifactId::Commit(commit) => {