feat: emit perf data in pipe mode

Author: art049

src/run/runner/wall_time/perf/mod.rs

@@ -41,7 +41,7 @@ pub mod perf_map;
 pub mod unwind_data;
 
 const PERF_METADATA_CURRENT_VERSION: u64 = 1;
-const PERF_DATA_PATH: &str = "/tmp/perf.data";
+const PERF_DATA_PATH: &str = "/tmp/perf.pipedata";
 
 pub struct PerfRunner {
     benchmark_data: OnceCell<BenchmarkData>,
@@ -139,12 +139,16 @@ impl PerfRunner {
                 perf_fifo.ctl_fifo_path.to_string_lossy(),
                 perf_fifo.ack_fifo_path.to_string_lossy()
             ),
-            &format!("--output={PERF_DATA_PATH}"),
+            "-o",
+            "-", // forces pipe mode
             "--",
         ]);
         cmd_builder.wrap_with(perf_wrapper_builder);
-        let cmd = wrap_with_sudo(cmd_builder)?.build();
-        debug!("cmd: {cmd:?}");
+        let raw_command = format!("{} | cat > PERF_DATA_PATH", &cmd_builder.as_command_line());
+        let mut wrapped_builder = CommandBuilder::new("sh");
+        wrapped_builder.args(["-c", &raw_command]);
+        let cmd = wrap_with_sudo(wrapped_builder)?.build();
+        println!("cmd: {cmd:?}");
 
         let on_process_started = async |_| -> anyhow::Result<()> {
             let data = Self::handle_fifo(runner_fifo, perf_fifo).await?;
@@ -174,7 +178,7 @@ impl PerfRunner {
         )?;
 
         // Copy the perf data to the profile folder
-        let perf_data_dest = profile_folder.join("perf.data");
+        let perf_data_dest = profile_folder.join("perf.pipedata");
         std::fs::copy(PERF_DATA_PATH, &perf_data_dest)
             .with_context(|| format!("Failed to copy perf data to {perf_data_dest:?}",))?;