Merge remote-tracking branch 'upstream/master' into dp-target-is-cow

* upstream/master:
  subscriber: remove TraceLogger (tokio-rs#1052)
  subscriber: make Registry::enter/exit much faster (tokio-rs#1058)
  chore(deps): update env_logger requirement from 0.7 to 0.8 (tokio-rs#1050)

examples/Cargo.toml

@@ -30,7 +30,7 @@ futures = "0.3"
 tokio = { version = "0.2.12", features = ["full"] }
 
 # env-logger example
-env_logger = "0.7"
+env_logger = "0.8"
 
 # tower examples
 tower = "0.3"

tracing-log/Cargo.toml

@@ -17,16 +17,15 @@ license = "MIT"
 readme = "README.md"
 
 [features]
-default = ["log-tracer", "trace-logger", "std"]
+default = ["log-tracer", "std"]
 std = ["log/std"]
 log-tracer = []
-trace-logger = []
 
 [dependencies]
 tracing-core = { path = "../tracing-core", version = "0.2"}
 log = { version = "0.4" }
 lazy_static = "1.3.0"
-env_logger = { version = "0.7", optional = true }
+env_logger = { version = "0.8", optional = true }
 
 [dev-dependencies]
 tracing = { path = "../tracing", version = "0.2"}

tracing-log/src/lib.rs

@@ -59,18 +59,16 @@
 //!
 //! Note that logger implementations that convert log records to trace events
 //! should not be used with `Subscriber`s that convert trace events _back_ into
-//! log records (such as the `TraceLogger`), as doing so will result in the
-//! event recursing between the subscriber and the logger forever (or, in real
-//! life, probably overflowing the call stack).
+//! log records, as doing so will result in the event recursing between the
+//! subscriber and the logger forever (or, in real life, probably overflowing
+//! the call stack).
 //!
 //! If the logging of trace events generated from log records produced by the
 //! `log` crate is desired, either the `log` crate should not be used to
 //! implement this logging, or an additional layer of filtering will be
 //! required to avoid infinitely converting between `Event` and `log::Record`.
 //!
 //! # Feature Flags
-//! * `trace-logger`: enables an experimental `log` subscriber, deprecated since
-//!   version 0.1.1.
 //! * `log-tracer`: enables the `LogTracer` type (on by default)
 //! * `env_logger`: enables the `env_logger` module, with helpers for working
 //!   with the [`env_logger` crate].
@@ -94,7 +92,6 @@
 //! [`AsTrace`]: trait.AsTrace.html
 //! [`AsLog`]: trait.AsLog.html
 //! [`LogTracer`]: struct.LogTracer.html
-//! [`TraceLogger`]: struct.TraceLogger.html
 //! [`env_logger`]: env_logger/index.html
 //! [`tracing`]: https://crates.io/crates/tracing
 //! [`log`]: https://crates.io/crates/log
@@ -151,25 +148,11 @@ use tracing_core::{
 #[cfg_attr(docsrs, doc(cfg(feature = "log-tracer")))]
 pub mod log_tracer;
 
-#[cfg(feature = "trace-logger")]
-#[cfg_attr(docsrs, doc(cfg(feature = "trace-logger")))]
-pub mod trace_logger;
-
 #[cfg(feature = "log-tracer")]
 #[cfg_attr(docsrs, doc(cfg(feature = "log-tracer")))]
 #[doc(inline)]
 pub use self::log_tracer::LogTracer;
 
-#[cfg(feature = "trace-logger")]
-#[cfg_attr(docsrs, doc(cfg(feature = "trace-logger")))]
-#[deprecated(
-    since = "0.1.1",
-    note = "use the `tracing` crate's \"log\" feature flag instead"
-)]
-#[allow(deprecated)]
-#[doc(inline)]
-pub use self::trace_logger::TraceLogger;
-
 #[cfg(feature = "env_logger")]
 #[cfg_attr(docsrs, doc(cfg(feature = "env_logger")))]
 pub mod env_logger;

tracing-subscriber/Cargo.toml

@@ -84,3 +84,7 @@ harness = false
 [[bench]]
 name = "fmt"
 harness = false
+
+[[bench]]
+name = "enter"
+harness = false

tracing-subscriber/benches/enter.rs

@@ -0,0 +1,64 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use tracing_subscriber::prelude::*;
+
+fn enter(c: &mut Criterion) {
+    let mut group = c.benchmark_group("enter");
+    let _subscriber = tracing_subscriber::fmt()
+        .with_max_level(tracing::Level::INFO)
+        .finish()
+        .set_default();
+    group.bench_function("enabled", |b| {
+        let span = tracing::info_span!("foo");
+        b.iter_with_large_drop(|| span.enter())
+    });
+    group.bench_function("disabled", |b| {
+        let span = tracing::debug_span!("foo");
+        b.iter_with_large_drop(|| span.enter())
+    });
+}
+
+fn enter_exit(c: &mut Criterion) {
+    let mut group = c.benchmark_group("enter_exit");
+    let _subscriber = tracing_subscriber::fmt()
+        .with_max_level(tracing::Level::INFO)
+        .finish()
+        .set_default();
+    group.bench_function("enabled", |b| {
+        let span = tracing::info_span!("foo");
+        b.iter(|| span.enter())
+    });
+    group.bench_function("disabled", |b| {
+        let span = tracing::debug_span!("foo");
+        b.iter(|| span.enter())
+    });
+}
+
+fn enter_many(c: &mut Criterion) {
+    let mut group = c.benchmark_group("enter_many");
+    let _subscriber = tracing_subscriber::fmt()
+        .with_max_level(tracing::Level::INFO)
+        .finish()
+        .set_default();
+    group.bench_function("enabled", |b| {
+        let span1 = tracing::info_span!("span1");
+        let _e1 = span1.enter();
+        let span2 = tracing::info_span!("span2");
+        let _e2 = span2.enter();
+        let span3 = tracing::info_span!("span3");
+        let _e3 = span3.enter();
+        let span = tracing::info_span!("foo");
+        b.iter_with_large_drop(|| span.enter())
+    });
+    group.bench_function("disabled", |b| {
+        let span1 = tracing::info_span!("span1");
+        let _e1 = span1.enter();
+        let span2 = tracing::info_span!("span2");
+        let _e2 = span2.enter();
+        let span3 = tracing::info_span!("span3");
+        let _e3 = span3.enter();
+        let span = tracing::debug_span!("foo");
+        b.iter_with_large_drop(|| span.enter())
+    });
+}
+criterion_group!(benches, enter, enter_exit, enter_many);
+criterion_main!(benches);

tracing-subscriber/src/registry/sharded.rs

@@ -202,19 +202,21 @@ impl Subscriber for Registry {
     fn event(&self, _: &Event<'_>) {}
 
     fn enter(&self, id: &span::Id) {
-        self.current_spans
+        if self
+            .current_spans
             .get_or_default()
             .borrow_mut()
-            .push(self.clone_span(id));
+            .push(id.clone())
+        {
+            self.clone_span(id);
+        }
     }
 
     fn exit(&self, id: &span::Id) {
-        if let Some(id) = self
-            .current_spans
-            .get()
-            .and_then(|spans| spans.borrow_mut().pop(id))
-        {
-            dispatcher::get_default(|dispatch| dispatch.try_close(id.clone()));
+        if let Some(spans) = self.current_spans.get() {
+            if spans.borrow_mut().pop(id) {
+                dispatcher::get_default(|dispatch| dispatch.try_close(id.clone()));
+            }
         }
     }
 

tracing-subscriber/src/registry/stack.rs

@@ -1,5 +1,3 @@
-use std::collections::HashSet;
-
 pub(crate) use tracing_core::span::Id;
 
 #[derive(Debug)]
@@ -15,34 +13,29 @@ struct ContextId {
 #[derive(Debug, Default)]
 pub(crate) struct SpanStack {
     stack: Vec<ContextId>,
-    ids: HashSet<Id>,
 }
 
 impl SpanStack {
-    pub(crate) fn push(&mut self, id: Id) {
-        let duplicate = self.ids.contains(&id);
-        if !duplicate {
-            self.ids.insert(id.clone());
-        }
-        self.stack.push(ContextId { id, duplicate })
+    #[inline]
+    pub(crate) fn push(&mut self, id: Id) -> bool {
+        let duplicate = self.stack.iter().any(|i| i.id == id);
+        self.stack.push(ContextId { id, duplicate });
+        !duplicate
     }
 
-    pub(crate) fn pop(&mut self, expected_id: &Id) -> Option<Id> {
+    #[inline]
+    pub(crate) fn pop(&mut self, expected_id: &Id) -> bool {
         if let Some((idx, _)) = self
             .stack
             .iter()
             .enumerate()
             .rev()
             .find(|(_, ctx_id)| ctx_id.id == *expected_id)
         {
-            let ContextId { id, duplicate } = self.stack.remove(idx);
-            if !duplicate {
-                self.ids.remove(&id);
-            }
-            Some(id)
-        } else {
-            None
+            let ContextId { id: _, duplicate } = self.stack.remove(idx);
+            return !duplicate;
         }
+        false
     }
 
     #[inline]
@@ -65,7 +58,7 @@ mod tests {
         let id = Id::from_u64(1);
         stack.push(id.clone());
 
-        assert_eq!(Some(id.clone()), stack.pop(&id));
+        assert!(stack.pop(&id));
     }
 
     #[test]
@@ -75,6 +68,6 @@ mod tests {
         stack.push(Id::from_u64(2));
 
         let id = Id::from_u64(1);
-        assert_eq!(Some(id.clone()), stack.pop(&id));
+        assert!(stack.pop(&id));
     }
 }