rearrange to reduce time inside lock to minimal

Author: cijothomas

opentelemetry-sdk/src/metrics/internal/aggregate.rs

@@ -12,7 +12,7 @@ use super::{
     precomputed_sum::PrecomputedSum, sum::Sum, Number,
 };
 
-pub(crate) const STREAM_CARDINALITY_LIMIT: u32 = 2000;
+pub(crate) const STREAM_CARDINALITY_LIMIT: usize = 2000;
 
 /// Checks whether aggregator has hit cardinality limit for metric streams
 pub(crate) fn is_under_cardinality_limit(size: usize) -> bool {

opentelemetry-sdk/src/metrics/internal/mod.rs

@@ -72,14 +72,10 @@ where
 {
     fn new(config: A::InitConfig) -> Self {
         ValueMap {
-            trackers: RwLock::new(HashMap::with_capacity(
-                1 + STREAM_CARDINALITY_LIMIT as usize,
-            )),
+            trackers: RwLock::new(HashMap::with_capacity(1 + STREAM_CARDINALITY_LIMIT)),
             // TODO: For cumulative, this is not required, so avoid this
             // pre-allocation.
-            trackers_for_collect: RwLock::new(HashMap::with_capacity(
-                1 + STREAM_CARDINALITY_LIMIT as usize,
-            )),
+            trackers_for_collect: RwLock::new(HashMap::with_capacity(1 + STREAM_CARDINALITY_LIMIT)),
             has_no_attribute_value: AtomicBool::new(false),
             no_attribute_tracker: A::create(&config),
             count: AtomicUsize::new(0),
@@ -182,28 +178,23 @@ where
             ));
         }
 
-        let mut trackers = if let Ok(mut trackers_guard) = self.trackers.write() {
-            if let Ok(mut trackers_for_collect_guard) = self.trackers_for_collect.write() {
-                swap(
-                    trackers_guard.deref_mut(),
-                    trackers_for_collect_guard.deref_mut(),
-                );
+        if let Ok(mut trackers_collect) = self.trackers_for_collect.write() {
+            if let Ok(mut trackers_current) = self.trackers.write() {
+                swap(trackers_collect.deref_mut(), trackers_current.deref_mut());
                 self.count.store(0, Ordering::SeqCst);
-                trackers_for_collect_guard
             } else {
-                otel_warn!(name: "MeterProvider.InternalError", message = "Metric collection failed. Report this issue in OpenTelemetry repo.", details ="ValueMap trackers for collect lock poisoned");
+                otel_warn!(name: "MeterProvider.InternalError", message = "Metric collection failed. Report this issue in OpenTelemetry repo.", details ="ValueMap trackers lock poisoned");
                 return;
             }
-        } else {
-            otel_warn!(name: "MeterProvider.InternalError", message = "Metric collection failed. Report this issue in OpenTelemetry repo.", details ="ValueMap trackers lock poisoned");
-            return;
-        };
 
-        let mut seen = HashSet::new();
-        for (attrs, tracker) in trackers.drain() {
-            if seen.insert(Arc::as_ptr(&tracker)) {
-                dest.push(map_fn(attrs, tracker.clone_and_reset(&self.config)));
+            let mut seen = HashSet::new();
+            for (attrs, tracker) in trackers_collect.drain() {
+                if seen.insert(Arc::as_ptr(&tracker)) {
+                    dest.push(map_fn(attrs, tracker.clone_and_reset(&self.config)));
+                }
             }
+        } else {
+            otel_warn!(name: "MeterProvider.InternalError", message = "Metric collection failed. Report this issue in OpenTelemetry repo.", details ="ValueMap trackers for collect lock poisoned");
         }
     }
 }