perf: avoid expensive lookup of storage metrics (near#7495)

* perf: avoid expensive lookup of storage metrics

Finding the counter of a metric is a relatively expensive operation,
when compared to just updating its value. A performance regression
of about 20% on read perfromance has been observed due to additional
metrics added in near#7429.

This commit stores the counters in `TrieCacheInne` and
`TrieCachingStorag` to avoid the lookup in hot paths like when
we hit the shard or chunk cache.

* apply reviewer suggestions

- group metrics together in two new structs
- update comments

core/store/src/trie/trie_storage.rs

@@ -2,6 +2,8 @@ use std::borrow::Borrow;
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::sync::{Arc, Mutex};
 
+use near_metrics::prometheus;
+use near_metrics::prometheus::core::{GenericCounter, GenericGauge};
 use near_primitives::hash::CryptoHash;
 
 use crate::db::refcount::decode_value_with_rc;
@@ -73,6 +75,18 @@ pub struct TrieCacheInner {
     shard_id: u32,
     /// Whether cache is used for view calls execution.
     is_view: bool,
+    // Counters tracking operations happening inside the shard cache.
+    // Stored here to avoid overhead of looking them up on hot paths.
+    metrics: TrieCacheMetrics,
+}
+
+struct TrieCacheMetrics {
+    shard_cache_too_large: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_pop_hits: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_pop_misses: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_pop_lru: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_gc_pop_misses: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_deletions_size: GenericGauge<prometheus::core::AtomicI64>,
 }
 
 impl TrieCacheInner {
@@ -84,13 +98,27 @@ impl TrieCacheInner {
         is_view: bool,
     ) -> Self {
         assert!(cache_capacity > 0 && total_size_limit > 0);
+        let metrics_labels: [&str; 2] = [&format!("{}", shard_id), &format!("{}", is_view as u8)];
+        let metrics = TrieCacheMetrics {
+            shard_cache_too_large: metrics::SHARD_CACHE_TOO_LARGE
+                .with_label_values(&metrics_labels),
+            shard_cache_pop_hits: metrics::SHARD_CACHE_POP_HITS.with_label_values(&metrics_labels),
+            shard_cache_pop_misses: metrics::SHARD_CACHE_POP_MISSES
+                .with_label_values(&metrics_labels),
+            shard_cache_pop_lru: metrics::SHARD_CACHE_POP_LRU.with_label_values(&metrics_labels),
+            shard_cache_gc_pop_misses: metrics::SHARD_CACHE_GC_POP_MISSES
+                .with_label_values(&metrics_labels),
+            shard_cache_deletions_size: metrics::SHARD_CACHE_DELETIONS_SIZE
+                .with_label_values(&metrics_labels),
+        };
         Self {
             cache: LruCache::new(cache_capacity),
             deletions: BoundedQueue::new(deletions_queue_capacity),
             total_size: 0,
             total_size_limit,
             shard_id,
             is_view,
+            metrics,
         }
     }
 
@@ -105,26 +133,24 @@ impl TrieCacheInner {
     }
 
     pub(crate) fn put(&mut self, key: CryptoHash, value: Arc<[u8]>) {
-        let metrics_labels: [&str; 2] =
-            [&format!("{}", self.shard_id), &format!("{}", self.is_view as u8)];
         while self.total_size > self.total_size_limit || self.cache.len() == self.cache.cap() {
             // First, try to evict value using the key from deletions queue.
             match self.deletions.pop() {
                 Some(key) => match self.cache.pop(&key) {
                     Some(value) => {
-                        metrics::SHARD_CACHE_POP_HITS.with_label_values(&metrics_labels).inc();
+                        self.metrics.shard_cache_pop_hits.inc();
                         self.total_size -= value.len() as u64;
                         continue;
                     }
                     None => {
-                        metrics::SHARD_CACHE_POP_MISSES.with_label_values(&metrics_labels).inc();
+                        self.metrics.shard_cache_pop_misses.inc();
                     }
                 },
                 None => {}
             }
 
             // Second, pop LRU value.
-            metrics::SHARD_CACHE_POP_LRU.with_label_values(&metrics_labels).inc();
+            self.metrics.shard_cache_pop_lru.inc();
             let (_, value) =
                 self.cache.pop_lru().expect("Cannot fail because total size capacity is > 0");
             self.total_size -= value.len() as u64;
@@ -144,30 +170,26 @@ impl TrieCacheInner {
     // Adds key to the deletions queue if it is present in cache.
     // Returns key-value pair which are popped if deletions queue is full.
     pub(crate) fn pop(&mut self, key: &CryptoHash) -> Option<(CryptoHash, Arc<[u8]>)> {
-        let metrics_labels: [&str; 2] =
-            [&format!("{}", self.shard_id), &format!("{}", self.is_view as u8)];
-        metrics::SHARD_CACHE_DELETIONS_SIZE
-            .with_label_values(&metrics_labels)
-            .set(self.deletions.len() as i64);
+        self.metrics.shard_cache_deletions_size.set(self.deletions.len() as i64);
         // Do nothing if key was removed before.
         if self.cache.contains(key) {
             // Put key to the queue of deletions and possibly remove another key we have to delete.
             match self.deletions.put(key.clone()) {
                 Some(key_to_delete) => match self.cache.pop(&key_to_delete) {
                     Some(evicted_value) => {
-                        metrics::SHARD_CACHE_POP_HITS.with_label_values(&metrics_labels).inc();
+                        self.metrics.shard_cache_pop_hits.inc();
                         self.total_size -= evicted_value.len() as u64;
                         Some((key_to_delete, evicted_value))
                     }
                     None => {
-                        metrics::SHARD_CACHE_POP_MISSES.with_label_values(&metrics_labels).inc();
+                        self.metrics.shard_cache_pop_misses.inc();
                         None
                     }
                 },
                 None => None,
             }
         } else {
-            metrics::SHARD_CACHE_GC_POP_MISSES.with_label_values(&metrics_labels).inc();
+            self.metrics.shard_cache_gc_pop_misses.inc();
             None
         }
     }
@@ -210,15 +232,13 @@ impl TrieCache {
 
     pub fn update_cache(&self, ops: Vec<(CryptoHash, Option<&Vec<u8>>)>) {
         let mut guard = self.0.lock().expect(POISONED_LOCK_ERR);
-        let metrics_labels: [&str; 2] =
-            [&format!("{}", guard.shard_id), &format!("{}", guard.is_view as u8)];
         for (hash, opt_value_rc) in ops {
             if let Some(value_rc) = opt_value_rc {
                 if let (Some(value), _rc) = decode_value_with_rc(&value_rc) {
                     if value.len() < TRIE_LIMIT_CACHED_VALUE_SIZE {
                         guard.put(hash, value.into());
                     } else {
-                        metrics::SHARD_CACHE_TOO_LARGE.with_label_values(&metrics_labels).inc();
+                        guard.metrics.shard_cache_too_large.inc();
                     }
                 } else {
                     guard.pop(&hash);
@@ -350,7 +370,6 @@ pub(crate) const TRIE_LIMIT_CACHED_VALUE_SIZE: usize = 1000;
 pub struct TrieCachingStorage {
     pub(crate) store: Store,
     pub(crate) shard_uid: ShardUId,
-    is_view: bool,
 
     /// Caches ever requested items for the shard `shard_uid`. Used to speed up DB operations, presence of any item is
     /// not guaranteed.
@@ -369,6 +388,20 @@ pub struct TrieCachingStorage {
     pub(crate) db_read_nodes: Cell<u64>,
     /// Counts trie nodes retrieved from the chunk cache.
     pub(crate) mem_read_nodes: Cell<u64>,
+    // Counters tracking operations happening inside the shard cache.
+    // Stored here to avoid overhead of looking them up on hot paths.
+    metrics: TrieCacheInnerMetrics,
+}
+
+struct TrieCacheInnerMetrics {
+    chunk_cache_hits: GenericCounter<prometheus::core::AtomicU64>,
+    chunk_cache_misses: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_hits: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_misses: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_too_large: GenericCounter<prometheus::core::AtomicU64>,
+    shard_cache_size: GenericGauge<prometheus::core::AtomicI64>,
+    chunk_cache_size: GenericGauge<prometheus::core::AtomicI64>,
+    shard_cache_current_total_size: GenericGauge<prometheus::core::AtomicI64>,
 }
 
 impl TrieCachingStorage {
@@ -378,15 +411,29 @@ impl TrieCachingStorage {
         shard_uid: ShardUId,
         is_view: bool,
     ) -> TrieCachingStorage {
+        let metrics_labels: [&str; 2] =
+            [&format!("{}", shard_uid.shard_id), &format!("{}", is_view as u8)];
+        let metrics = TrieCacheInnerMetrics {
+            chunk_cache_hits: metrics::CHUNK_CACHE_HITS.with_label_values(&metrics_labels),
+            chunk_cache_misses: metrics::CHUNK_CACHE_MISSES.with_label_values(&metrics_labels),
+            shard_cache_hits: metrics::SHARD_CACHE_HITS.with_label_values(&metrics_labels),
+            shard_cache_misses: metrics::SHARD_CACHE_MISSES.with_label_values(&metrics_labels),
+            shard_cache_too_large: metrics::SHARD_CACHE_TOO_LARGE
+                .with_label_values(&metrics_labels),
+            shard_cache_size: metrics::SHARD_CACHE_SIZE.with_label_values(&metrics_labels),
+            chunk_cache_size: metrics::CHUNK_CACHE_SIZE.with_label_values(&metrics_labels),
+            shard_cache_current_total_size: metrics::SHARD_CACHE_CURRENT_TOTAL_SIZE
+                .with_label_values(&metrics_labels),
+        };
         TrieCachingStorage {
             store,
             shard_uid,
-            is_view,
             shard_cache,
             cache_mode: Cell::new(TrieCacheMode::CachingShard),
             chunk_cache: RefCell::new(Default::default()),
             db_read_nodes: Cell::new(0),
             mem_read_nodes: Cell::new(0),
+            metrics,
         }
     }
 
@@ -427,35 +474,28 @@ impl TrieCachingStorage {
 
 impl TrieStorage for TrieCachingStorage {
     fn retrieve_raw_bytes(&self, hash: &CryptoHash) -> Result<Arc<[u8]>, StorageError> {
-        let metrics_labels: [&str; 2] =
-            [&format!("{}", self.shard_uid.shard_id), &format!("{}", self.is_view as u8)];
-
-        metrics::CHUNK_CACHE_SIZE
-            .with_label_values(&metrics_labels)
-            .set(self.chunk_cache.borrow().len() as i64);
+        self.metrics.chunk_cache_size.set(self.chunk_cache.borrow().len() as i64);
         // Try to get value from chunk cache containing nodes with cheaper access. We can do it for any `TrieCacheMode`,
         // because we charge for reading nodes only when `CachingChunk` mode is enabled anyway.
         if let Some(val) = self.chunk_cache.borrow_mut().get(hash) {
-            metrics::CHUNK_CACHE_HITS.with_label_values(&metrics_labels).inc();
+            self.metrics.chunk_cache_hits.inc();
             self.inc_mem_read_nodes();
             return Ok(val.clone());
         }
-        metrics::CHUNK_CACHE_MISSES.with_label_values(&metrics_labels).inc();
+        self.metrics.chunk_cache_misses.inc();
 
         // Try to get value from shard cache containing most recently touched nodes.
         let mut guard = self.shard_cache.0.lock().expect(POISONED_LOCK_ERR);
-        metrics::SHARD_CACHE_SIZE.with_label_values(&metrics_labels).set(guard.len() as i64);
-        metrics::SHARD_CACHE_CURRENT_TOTAL_SIZE
-            .with_label_values(&metrics_labels)
-            .set(guard.current_total_size() as i64);
+        self.metrics.shard_cache_size.set(guard.len() as i64);
+        self.metrics.shard_cache_current_total_size.set(guard.current_total_size() as i64);
         let val = match guard.get(hash) {
             Some(val) => {
-                metrics::SHARD_CACHE_HITS.with_label_values(&metrics_labels).inc();
+                self.metrics.shard_cache_hits.inc();
                 near_o11y::io_trace!(count: "shard_cache_hit");
                 val.clone()
             }
             None => {
-                metrics::SHARD_CACHE_MISSES.with_label_values(&metrics_labels).inc();
+                self.metrics.shard_cache_misses.inc();
                 near_o11y::io_trace!(count: "shard_cache_miss");
                 // If value is not present in cache, get it from the storage.
                 let key = Self::get_key_from_shard_uid_and_hash(self.shard_uid, hash);
@@ -475,7 +515,7 @@ impl TrieStorage for TrieCachingStorage {
                 if val.len() < TRIE_LIMIT_CACHED_VALUE_SIZE {
                     guard.put(*hash, val.clone());
                 } else {
-                    metrics::SHARD_CACHE_TOO_LARGE.with_label_values(&metrics_labels).inc();
+                    self.metrics.shard_cache_too_large.inc();
                     near_o11y::io_trace!(count: "shard_cache_too_large");
                 }