feat: support linux profiling with samply (opt-in)

Cargo.toml

@@ -75,7 +75,7 @@ rmp-serde = "1.3.0"
 uuid = { version = "1.21.0", features = ["v4"] }
 which = "8.0.2"
 crc32fast = "1.5.0"
-samply = { git = "https://github.com/CodSpeedHQ/samply-codspeed", branch = "codspeed" }
+samply = { git = "https://github.com/CodSpeedHQ/samply-codspeed", rev = "72d93a3a" } # branch = "codspeed"
 
 [target.'cfg(target_os = "linux")'.dependencies]
 procfs = "0.17.0"

src/executor/helpers/command.rs

@@ -48,7 +48,6 @@ impl CommandBuilder {
         self
     }
 
-    #[cfg(target_os = "macos")]
     pub fn env<K, V>(&mut self, key: K, value: V) -> &mut Self
     where
         K: AsRef<OsStr>,
@@ -59,6 +58,18 @@ impl CommandBuilder {
         self
     }
 
+    pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Self
+    where
+        I: IntoIterator<Item = (K, V)>,
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>,
+    {
+        for (k, v) in vars {
+            self.env(k, v);
+        }
+        self
+    }
+
     pub fn current_dir<D>(&mut self, dir: D)
     where
         D: AsRef<OsStr>,

src/executor/wall_time/executor.rs

@@ -88,24 +88,41 @@ pub struct WallTimeExecutor {
     benchmark_state: OnceCell<(FifoBenchmarkData, ExecutionTimestamps)>,
 }
 
+fn select_profiler() -> Option<Box<dyn Profiler>> {
+    const PROFILER_OVERRIDE_ENV: &str = "CODSPEED_WALLTIME_PROFILER";
+
+    match std::env::var(PROFILER_OVERRIDE_ENV).ok().as_deref() {
+        Some("perf") => return Some(Box::new(PerfProfiler::new())),
+        Some("samply") => return Some(Box::new(SamplyProfiler::new())),
+        Some(other) => {
+            warn!(
+                "Ignoring unknown {PROFILER_OVERRIDE_ENV}={other:?}; expected `perf` or `samply`."
+            );
+        }
+        None => {}
+    }
+
+    if cfg!(target_os = "linux") {
+        Some(Box::new(PerfProfiler::new()))
+    } else if cfg!(target_os = "macos") {
+        Some(Box::new(SamplyProfiler::new()))
+    } else {
+        None
+    }
+}
+
 impl WallTimeExecutor {
     pub fn new() -> Self {
-        let profiler: Option<Box<dyn Profiler>> = if cfg!(target_os = "linux") {
-            Some(Box::new(PerfProfiler::new()))
-        } else if cfg!(target_os = "macos") {
-            Some(Box::new(SamplyProfiler::new()))
-        } else {
-            None
-        };
         Self {
-            profiler,
+            profiler: select_profiler(),
             benchmark_state: OnceCell::new(),
         }
     }
 
     fn walltime_bench_cmd(
         config: &ExecutorConfig,
         execution_context: &ExecutionContext,
+        isolate: bool,
     ) -> Result<(NamedTempFile, NamedTempFile, CommandBuilder)> {
         let path_value = build_path_env(config.enable_introspection)?;
 
@@ -130,7 +147,11 @@ impl WallTimeExecutor {
             bench_cmd.current_dir(abs_cwd);
         }
 
-        let bench_cmd = wrap_with_isolation(bench_cmd)?;
+        let bench_cmd = if isolate {
+            wrap_with_isolation(bench_cmd)?
+        } else {
+            bench_cmd
+        };
 
         Ok((env_file, script_file, bench_cmd))
     }
@@ -168,8 +189,15 @@ impl Executor for WallTimeExecutor {
     ) -> Result<()> {
         let _guard = HookScriptsGuard::setup();
 
-        let (_env_file, _script_file, cmd_builder) =
-            WallTimeExecutor::walltime_bench_cmd(&execution_context.config, execution_context)?;
+        let isolate = self
+            .profiler
+            .as_ref()
+            .is_none_or(|p| p.requires_isolation());
+        let (_env_file, _script_file, cmd_builder) = WallTimeExecutor::walltime_bench_cmd(
+            &execution_context.config,
+            execution_context,
+            isolate,
+        )?;
 
         // Split-borrow `self` so the closure inside `run_with_profiler` can
         // capture `benchmark_state` while we hold `&mut profiler`.

src/executor/wall_time/profiler/mod.rs

@@ -33,6 +33,12 @@ pub trait Profiler {
         None
     }
 
+    /// Whether the benchmark command should be wrapped with the Linux
+    /// systemd-run isolation scope.
+    fn requires_isolation(&self) -> bool {
+        true
+    }
+
     /// One-time system setup (install tool, tweak sysctls, ...).
     async fn setup(
         &self,

src/executor/wall_time/profiler/samply/mod.rs

@@ -46,6 +46,10 @@ impl SamplyProfiler {
 
 #[async_trait(?Send)]
 impl Profiler for SamplyProfiler {
+    fn requires_isolation(&self) -> bool {
+        false
+    }
+
     async fn setup(
         &self,
         _system_info: &SystemInfo,
@@ -101,6 +105,17 @@ impl Profiler for SamplyProfiler {
 
         cmd_builder.wrap_with(samply_builder);
 
+        cmd_builder.envs([
+            // Disable JIT classification as it produces duplicates symbols in
+            // Node.js for the Interpreter frames.
+            ("SAMPLY_DISABLE_JIT_CLASSIFICATION", "1"),
+            ("SAMPLY_USE_DEBUGINFOD", "1"),
+            (
+                "SAMPLY_BREAKPAD_SYMBOL_SERVER",
+                "https://symbols.mozilla.org/,https://symbols.electronjs.org/",
+            ),
+        ]);
+
         // If `setup` decided the bash on PATH is Apple-signed, prepend brew's
         // bin so samply's spawned shell resolves to the ad-hoc-signed brew bash
         // instead. Only the samply child's PATH is touched.