From 3f70c22858c93c44a22cf9c8ebcd1073b056909f Mon Sep 17 00:00:00 2001
From: Guillaume Lagrange <guillaume@glagrange.eu>
Date: Fri, 7 Nov 2025 11:52:37 +0100
Subject: [PATCH] feat: add more events to perf monitoring

---
 src/run/runner/wall_time/perf/mod.rs          |  7 ++-
 .../runner/wall_time/perf/perf_executable.rs  | 43 +++++++++++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/src/run/runner/wall_time/perf/mod.rs b/src/run/runner/wall_time/perf/mod.rs
index 7e4c8220..c3117d9f 100644
--- a/src/run/runner/wall_time/perf/mod.rs
+++ b/src/run/runner/wall_time/perf/mod.rs
@@ -19,6 +19,7 @@ use fifo::{PerfFifo, RunnerFifo};
 use libc::pid_t;
 use nix::sys::time::TimeValLike;
 use nix::time::clock_gettime;
+use perf_executable::get_event_flags;
 use perf_map::ProcessSymbols;
 use runner_shared::debug_info::ModuleDebugInfo;
 use runner_shared::fifo::Command as FifoCommand;
@@ -120,11 +121,15 @@ impl PerfRunner {
 
         let working_perf_executable =
             get_working_perf_executable().context("Failed to find a working perf executable")?;
-        let mut perf_wrapper_builder = CommandBuilder::new(working_perf_executable);
+        let mut perf_wrapper_builder = CommandBuilder::new(&working_perf_executable);
         perf_wrapper_builder.arg("record");
         if !is_codspeed_debug_enabled() {
             perf_wrapper_builder.arg("--quiet");
         }
+        // Add events flag if all required events are available
+        if let Some(events_flag) = get_event_flags(&working_perf_executable)? {
+            perf_wrapper_builder.arg(events_flag);
+        }
         perf_wrapper_builder.args([
             "--timestamp",
             // Required for matching the markers and URIs to the samples.
diff --git a/src/run/runner/wall_time/perf/perf_executable.rs b/src/run/runner/wall_time/perf/perf_executable.rs
index 6da51cd6..623e5c48 100644
--- a/src/run/runner/wall_time/perf/perf_executable.rs
+++ b/src/run/runner/wall_time/perf/perf_executable.rs
@@ -62,3 +62,46 @@ pub fn get_working_perf_executable() -> Option<OsString> {
     debug!("perf is installed but not functioning correctly");
     None
 }
+
+/// Detects if the required perf events are available on this system.
+/// Returns Some("-e {cycles,cache-references,cache-misses}") if all three events are available,
+/// None otherwise.
+pub fn get_event_flags(perf_executable: &OsString) -> anyhow::Result<Option<String>> {
+    const CYCLES_EVENT_NAME: &str = "cycles";
+    const CACHE_REFERENCES_EVENT_NAME: &str = "cache-references";
+    const CACHE_MISSES_EVENT_NAME: &str = "cache-misses";
+
+    let perf_events = [
+        CYCLES_EVENT_NAME,
+        CACHE_REFERENCES_EVENT_NAME,
+        CACHE_MISSES_EVENT_NAME,
+    ];
+
+    let output = Command::new(perf_executable)
+        .arg("list")
+        .output()
+        .context("Failed to run perf list")?;
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+
+    // Check if all required events are available
+    let missing_events: Vec<&str> = perf_events
+        .iter()
+        .filter(|&&event| !stdout.lines().any(|line| line.trim().starts_with(event)))
+        .copied()
+        .collect();
+
+    if !missing_events.is_empty() {
+        debug!(
+            "Not all required perf events available. Missing: [{}], using default events",
+            missing_events.join(", ")
+        );
+        return Ok(None);
+    }
+
+    debug!(
+        "All required perf events available: {}",
+        perf_events.join(", ")
+    );
+    Ok(Some(format!("-e {{{}}}", perf_events.join(","))))
+}