add static metrics for multilevel queue

Signed-off-by: Yilin Chen <sticnarf@gmail.com>

Cargo.toml

@@ -14,6 +14,8 @@ parking_lot_core = "0.7"
 crossbeam-deque = "0.7"
 dashmap = "1.2.0"
 rand = "0.7"
+prometheus = "0.7"
+lazy_static = "1"
 
 [dev-dependencies]
 criterion = "0.3"

src/lib.rs

@@ -4,6 +4,7 @@
 
 //! Yatp is a thread pool that tries to be adaptive, responsive and generic.
 
+mod metrics;
 pub mod pool;
 pub mod queue;
 pub mod task;

src/metrics.rs

@@ -0,0 +1,21 @@
+use lazy_static::lazy_static;
+use prometheus::*;
+
+lazy_static! {
+    pub static ref MULTILEVEL_LEVEL_ELAPSED: IntCounterVec = IntCounterVec::new(
+        Opts::new(
+            "multilevel_level_elapsed",
+            "elapsed time of each level in the multilevel task queue"
+        ),
+        &["name", "level"]
+    )
+    .unwrap();
+    pub static ref MULTILEVEL_LEVEL0_CHANCE: GaugeVec = GaugeVec::new(
+        Opts::new(
+            "multilevel_level0_chance",
+            "the chance that a level 0 task is scheduled to run"
+        ),
+        &["name"]
+    )
+    .unwrap();
+}

src/pool.rs

@@ -14,7 +14,7 @@ pub use self::builder::{Builder, SchedConfig};
 pub use self::runner::{CloneRunnerBuilder, Runner, RunnerBuilder};
 pub use self::spawn::{build_spawn, Local, Remote};
 
-use crate::queue::{QueueStatistics, TaskCell, WithExtras};
+use crate::queue::{TaskCell, WithExtras};
 use std::mem;
 use std::sync::Mutex;
 use std::thread::JoinHandle;
@@ -48,11 +48,6 @@ impl<T: TaskCell + Send> ThreadPool<T> {
     pub fn remote(&self) -> &Remote<T> {
         &self.remote
     }
-
-    /// Gets the task queue statistics of the thread pool.
-    pub fn queue_statistics(&self) -> QueueStatistics {
-        self.remote.queue_statistics()
-    }
 }
 
 impl<T: TaskCell + Send> Drop for ThreadPool<T> {

src/pool/spawn.rs

@@ -5,7 +5,7 @@
 //! tasks waiting to be handled.
 
 use crate::pool::SchedConfig;
-use crate::queue::{Extras, LocalQueue, Pop, QueueStatistics, TaskCell, TaskInjector, WithExtras};
+use crate::queue::{Extras, LocalQueue, Pop, TaskCell, TaskInjector, WithExtras};
 use parking_lot_core::{ParkResult, ParkToken, UnparkToken};
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Arc;
@@ -131,10 +131,6 @@ impl<T: TaskCell + Send> QueueCore<T> {
     fn default_extras(&self) -> Extras {
         self.global_queue.default_extras()
     }
-
-    pub fn queue_statistics(&self) -> QueueStatistics {
-        self.global_queue.statistics()
-    }
 }
 
 /// Submits tasks to associated thread pool.
@@ -156,11 +152,6 @@ impl<T: TaskCell + Send> Remote<T> {
         self.core.push(0, t);
     }
 
-    /// Gets the task queue statistics of the thread pool.
-    pub fn queue_statistics(&self) -> QueueStatistics {
-        self.core.queue_statistics()
-    }
-
     pub(crate) fn stop(&self) {
         self.core.mark_shutdown(0);
     }

src/queue.rs

@@ -15,7 +15,6 @@ mod single_level;
 
 pub use self::extras::Extras;
 
-use self::multilevel::MultilevelStatistics;
 use std::time::Instant;
 
 /// A cell containing a task and needed extra information.
@@ -60,13 +59,6 @@ impl<T: TaskCell + Send> TaskInjector<T> {
             InjectorInner::Multilevel(_) => Extras::multilevel_default(),
         }
     }
-
-    pub(super) fn statistics(&self) -> QueueStatistics {
-        match &self.0 {
-            InjectorInner::SingleLevel(_) => QueueStatistics::SingleLevel,
-            InjectorInner::Multilevel(q) => QueueStatistics::Multilevel(q.statistics()),
-        }
-    }
 }
 
 /// Popped task cell from a task queue.
@@ -116,15 +108,6 @@ impl<T: TaskCell + Send> LocalQueue<T> {
     }
 }
 
-/// Statistics of the task queue.
-pub enum QueueStatistics {
-    // TODO: add statistics for single level queue
-    /// Statistics of a single-level queue.
-    SingleLevel,
-    /// Statistics of a multilevel queue.
-    Multilevel(MultilevelStatistics),
-}
-
 /// Supported available queues.
 pub enum QueueType {
     /// A single level work stealing queue.