metrics: stabilize RuntimeMetrics::worker_count (#6556)

tokio/src/macros/cfg.rs

@@ -215,7 +215,7 @@ macro_rules! cfg_macros {
     }
 }
 
-macro_rules! cfg_metrics {
+macro_rules! cfg_unstable_metrics {
     ($($item:item)*) => {
         $(
             #[cfg(tokio_unstable)]
@@ -245,7 +245,7 @@ macro_rules! cfg_no_64bit_metrics {
     }
 }
 
-macro_rules! cfg_not_metrics {
+macro_rules! cfg_not_unstable_metrics {
     ($($item:item)*) => {
         $(
             #[cfg(not(tokio_unstable))]

tokio/src/runtime/blocking/pool.rs

@@ -40,7 +40,7 @@ impl SpawnerMetrics {
         self.num_idle_threads.load(Ordering::Relaxed)
     }
 
-    cfg_metrics! {
+    cfg_unstable_metrics! {
         fn queue_depth(&self) -> usize {
             self.queue_depth.load(Ordering::Relaxed)
         }
@@ -474,7 +474,7 @@ impl Spawner {
     }
 }
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     impl Spawner {
         pub(crate) fn num_threads(&self) -> usize {
             self.inner.metrics.num_threads()

tokio/src/runtime/builder.rs

@@ -957,7 +957,7 @@ impl Builder {
         }
     }
 
-    cfg_metrics! {
+    cfg_unstable_metrics! {
         /// Enables tracking the distribution of task poll times.
         ///
         /// Task poll times are not instrumented by default as doing so requires

tokio/src/runtime/coop.rs

@@ -197,7 +197,7 @@ cfg_coop! {
     }
 
     cfg_rt! {
-        cfg_metrics! {
+        cfg_unstable_metrics! {
             #[inline(always)]
             fn inc_budget_forced_yield_count() {
                 let _ = context::with_current(|handle| {
@@ -206,7 +206,7 @@ cfg_coop! {
             }
         }
 
-        cfg_not_metrics! {
+        cfg_not_unstable_metrics! {
             #[inline(always)]
             fn inc_budget_forced_yield_count() {}
         }

tokio/src/runtime/handle.rs

@@ -1,6 +1,6 @@
 #[cfg(tokio_unstable)]
 use crate::runtime;
-use crate::runtime::{context, scheduler, RuntimeFlavor};
+use crate::runtime::{context, scheduler, RuntimeFlavor, RuntimeMetrics};
 
 /// Handle to the runtime.
 ///
@@ -393,19 +393,13 @@ impl Handle {
             owned_id.into()
         }
     }
-}
 
-cfg_metrics! {
-    use crate::runtime::RuntimeMetrics;
-
-    impl Handle {
     /// Returns a view that lets you get information about how the runtime
     /// is performing.
     pub fn metrics(&self) -> RuntimeMetrics {
         RuntimeMetrics::new(self.clone())
     }
 }
-}
 
 cfg_taskdump! {
     impl Handle {

tokio/src/runtime/io/metrics.rs

@@ -17,7 +17,7 @@ cfg_not_rt_and_metrics_and_net! {
 
 cfg_net! {
     cfg_rt! {
-        cfg_metrics! {
+        cfg_unstable_metrics! {
             pub(crate) use crate::runtime::IoDriverMetrics;
         }
     }

tokio/src/runtime/metrics/histogram.rs

@@ -1,5 +1,5 @@
-use crate::loom::sync::atomic::Ordering::Relaxed;
 use crate::util::metric_atomics::MetricAtomicU64;
+use std::sync::atomic::Ordering::Relaxed;
 
 use std::cmp;
 use std::ops::Range;

tokio/src/runtime/metrics/io.rs

@@ -1,6 +1,7 @@
 #![cfg_attr(not(feature = "net"), allow(dead_code))]
 
-use crate::{loom::sync::atomic::Ordering::Relaxed, util::metric_atomics::MetricAtomicU64};
+use crate::util::metric_atomics::MetricAtomicU64;
+use std::sync::atomic::Ordering::Relaxed;
 
 #[derive(Default)]
 pub(crate) struct IoDriverMetrics {

tokio/src/runtime/metrics/mod.rs

@@ -8,7 +8,10 @@
 //! [unstable]: crate#unstable-features
 #![allow(clippy::module_inception)]
 
-cfg_metrics! {
+mod runtime;
+pub use runtime::RuntimeMetrics;
+
+cfg_unstable_metrics! {
     mod batch;
     pub(crate) use batch::MetricsBatch;
 
@@ -17,9 +20,6 @@ cfg_metrics! {
     #[allow(unreachable_pub)] // rust-lang/rust#57411
     pub use histogram::HistogramScale;
 
-    mod runtime;
-    #[allow(unreachable_pub)] // rust-lang/rust#57411
-    pub use runtime::RuntimeMetrics;
 
     mod scheduler;
     pub(crate) use scheduler::SchedulerMetrics;
@@ -33,7 +33,7 @@ cfg_metrics! {
     }
 }
 
-cfg_not_metrics! {
+cfg_not_unstable_metrics! {
     mod mock;
 
     pub(crate) use mock::{SchedulerMetrics, WorkerMetrics, MetricsBatch, HistogramBuilder};

tokio/src/runtime/metrics/runtime.rs

@@ -1,10 +1,12 @@
 use crate::runtime::Handle;
 
+cfg_unstable_metrics! {
     use std::ops::Range;
     cfg_64bit_metrics! {
         use std::sync::atomic::Ordering::Relaxed;
     }
     use std::time::Duration;
+}
 
 /// Handle to the runtime's metrics.
 ///
@@ -45,6 +47,8 @@ impl RuntimeMetrics {
         self.handle.inner.num_workers()
     }
 
+    cfg_unstable_metrics! {
+
         /// Returns the number of additional threads spawned by the runtime.
         ///
         /// The number of workers is set by configuring `max_blocking_threads` on
@@ -839,10 +843,8 @@ impl RuntimeMetrics {
         pub fn blocking_queue_depth(&self) -> usize {
             self.handle.inner.blocking_queue_depth()
         }
-}
 
         cfg_net! {
-    impl RuntimeMetrics {
             cfg_64bit_metrics! {
                 /// Returns the number of file descriptors that have been registered with the
                 /// runtime's I/O driver.
@@ -930,3 +932,4 @@ cfg_net! {
             }
         }
     }
+}

tokio/src/runtime/metrics/worker.rs

@@ -1,8 +1,10 @@
-use crate::loom::sync::atomic::AtomicUsize;
-use crate::loom::sync::atomic::Ordering::Relaxed;
 use crate::runtime::metrics::Histogram;
 use crate::runtime::Config;
 use crate::util::metric_atomics::MetricAtomicU64;
+// This is NOT the Loom atomic. To avoid an unnecessary state explosion in loom,
+// all metrics use regular atomics.
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering::Relaxed;
 
 /// Retrieve runtime worker metrics.
 ///

tokio/src/runtime/mod.rs

@@ -388,21 +388,18 @@ cfg_rt! {
     mod thread_id;
     pub(crate) use thread_id::ThreadId;
 
-    cfg_metrics! {
-        mod metrics;
-        pub use metrics::{RuntimeMetrics, HistogramScale};
+    pub(crate) mod metrics;
+    pub use metrics::RuntimeMetrics;
 
-        pub(crate) use metrics::{MetricsBatch, SchedulerMetrics, WorkerMetrics, HistogramBuilder};
+    cfg_unstable_metrics! {
+        pub use metrics::HistogramScale;
 
         cfg_net! {
             pub(crate) use metrics::IoDriverMetrics;
         }
     }
 
-    cfg_not_metrics! {
-        pub(crate) mod metrics;
-        pub(crate) use metrics::{SchedulerMetrics, WorkerMetrics, MetricsBatch, HistogramBuilder};
-    }
+    pub(crate) use metrics::{MetricsBatch, SchedulerMetrics, WorkerMetrics, HistogramBuilder};
 
     /// After thread starts / before thread stops
     type Callback = std::sync::Arc<dyn Fn() + Send + Sync>;

tokio/src/runtime/runtime.rs

@@ -455,6 +455,12 @@ impl Runtime {
     pub fn shutdown_background(self) {
         self.shutdown_timeout(Duration::from_nanos(0));
     }
+
+    /// Returns a view that lets you get information about how the runtime
+    /// is performing.
+    pub fn metrics(&self) -> crate::runtime::RuntimeMetrics {
+        self.handle.metrics()
+    }
 }
 
 #[allow(clippy::single_match)] // there are comments in the error branch, so we don't want if-let
@@ -486,13 +492,3 @@ impl Drop for Runtime {
 impl std::panic::UnwindSafe for Runtime {}
 
 impl std::panic::RefUnwindSafe for Runtime {}
-
-cfg_metrics! {
-    impl Runtime {
-        /// Returns a view that lets you get information about how the runtime
-        /// is performing.
-        pub fn metrics(&self) -> crate::runtime::RuntimeMetrics {
-            self.handle.metrics()
-        }
-    }
-}

tokio/src/runtime/scheduler/current_thread/mod.rs

@@ -502,7 +502,7 @@ impl Handle {
     }
 }
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     impl Handle {
         pub(crate) fn scheduler_metrics(&self) -> &SchedulerMetrics {
             &self.shared.scheduler_metrics

tokio/src/runtime/scheduler/inject.rs

@@ -16,7 +16,7 @@ cfg_rt_multi_thread! {
     mod rt_multi_thread;
 }
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     mod metrics;
 }
 

tokio/src/runtime/scheduler/mod.rs

@@ -163,9 +163,6 @@ cfg_rt! {
         }
     }
 
-    cfg_metrics! {
-        use crate::runtime::{SchedulerMetrics, WorkerMetrics};
-
     impl Handle {
         pub(crate) fn num_workers(&self) -> usize {
             match self {
@@ -176,7 +173,12 @@ cfg_rt! {
                 Handle::MultiThreadAlt(handle) => handle.num_workers(),
             }
         }
+    }
 
+    cfg_unstable_metrics! {
+        use crate::runtime::{SchedulerMetrics, WorkerMetrics};
+
+        impl Handle {
             pub(crate) fn num_blocking_threads(&self) -> usize {
                 match_flavor!(self, Handle(handle) => handle.num_blocking_threads())
             }

tokio/src/runtime/scheduler/multi_thread/handle.rs

@@ -9,9 +9,7 @@ use crate::util::RngSeedGenerator;
 
 use std::fmt;
 
-cfg_metrics! {
 mod metrics;
-}
 
 cfg_taskdump! {
     mod taskdump;

tokio/src/runtime/scheduler/multi_thread/handle/metrics.rs

@@ -1,12 +1,15 @@
 use super::Handle;
 
+cfg_unstable_metrics! {
     use crate::runtime::{SchedulerMetrics, WorkerMetrics};
+}
 
 impl Handle {
     pub(crate) fn num_workers(&self) -> usize {
         self.shared.worker_metrics.len()
     }
 
+    cfg_unstable_metrics! {
         pub(crate) fn num_blocking_threads(&self) -> usize {
             // workers are currently spawned using spawn_blocking
             self.blocking_spawner
@@ -42,3 +45,4 @@ impl Handle {
             self.blocking_spawner.queue_depth()
         }
     }
+}

tokio/src/runtime/scheduler/multi_thread/queue.rs

@@ -546,7 +546,7 @@ impl<T> Steal<T> {
     }
 }
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     impl<T> Steal<T> {
         pub(crate) fn len(&self) -> usize {
             self.0.len() as _

tokio/src/runtime/scheduler/multi_thread/worker.rs

@@ -74,7 +74,7 @@ use std::cell::RefCell;
 use std::task::Waker;
 use std::time::Duration;
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     mod metrics;
 }
 

tokio/src/runtime/scheduler/multi_thread_alt/handle.rs

@@ -9,7 +9,7 @@ use crate::util::RngSeedGenerator;
 
 use std::fmt;
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     mod metrics;
 }
 

tokio/src/runtime/scheduler/multi_thread_alt/queue.rs

@@ -538,7 +538,7 @@ impl<T> Steal<T> {
     }
 }
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     impl<T> Steal<T> {
         pub(crate) fn len(&self) -> usize {
             self.0.len() as _

tokio/src/runtime/scheduler/multi_thread_alt/worker.rs

@@ -74,7 +74,7 @@ use std::cmp;
 use std::task::Waker;
 use std::time::Duration;
 
-cfg_metrics! {
+cfg_unstable_metrics! {
     mod metrics;
 }
 

tokio/src/runtime/tests/queue.rs

@@ -40,7 +40,7 @@ fn fits_256_one_at_a_time() {
         local.push_back_or_overflow(task, &inject, &mut stats);
     }
 
-    cfg_metrics! {
+    cfg_unstable_metrics! {
         assert_metrics!(stats, overflow_count == 0);
     }
 
@@ -98,7 +98,7 @@ fn overflow() {
         local.push_back_or_overflow(task, &inject, &mut stats);
     }
 
-    cfg_metrics! {
+    cfg_unstable_metrics! {
         assert_metrics!(stats, overflow_count == 1);
     }
 
@@ -128,7 +128,7 @@ fn steal_batch() {
 
     assert!(steal1.steal_into(&mut local2, &mut stats).is_some());
 
-    cfg_metrics! {
+    cfg_unstable_metrics! {
         assert_metrics!(stats, steal_count == 2);
     }
 
@@ -184,7 +184,7 @@ fn stress1() {
                 thread::yield_now();
             }
 
-            cfg_metrics! {
+            cfg_unstable_metrics! {
                 assert_metrics!(stats, steal_count == n as _);
             }