Vendor things

third-party/vendor/tracing-subscriber/benches/support/mod.rs

@@ -0,0 +1,49 @@
+use std::{
+    sync::{Arc, Barrier},
+    thread,
+    time::{Duration, Instant},
+};
+use tracing::dispatcher::Dispatch;
+
+#[derive(Clone)]
+pub(super) struct MultithreadedBench {
+    start: Arc<Barrier>,
+    end: Arc<Barrier>,
+    dispatch: Dispatch,
+}
+
+impl MultithreadedBench {
+    pub(super) fn new(dispatch: Dispatch) -> Self {
+        Self {
+            start: Arc::new(Barrier::new(5)),
+            end: Arc::new(Barrier::new(5)),
+            dispatch,
+        }
+    }
+
+    pub(super) fn thread(&self, f: impl FnOnce() + Send + 'static) -> &Self {
+        self.thread_with_setup(|start| {
+            start.wait();
+            f()
+        })
+    }
+
+    pub(super) fn thread_with_setup(&self, f: impl FnOnce(&Barrier) + Send + 'static) -> &Self {
+        let this = self.clone();
+        thread::spawn(move || {
+            let dispatch = this.dispatch.clone();
+            tracing::dispatcher::with_default(&dispatch, move || {
+                f(&this.start);
+                this.end.wait();
+            })
+        });
+        self
+    }
+
+    pub(super) fn run(&self) -> Duration {
+        self.start.wait();
+        let t0 = Instant::now();
+        self.end.wait();
+        t0.elapsed()
+    }
+}