Extract read-only cache stats (#32789)

* extract read-only cache stat

* rename stats

---------

Co-authored-by: HaoranYi <haoran.yi@solana.com>

accounts-db/src/read_only_accounts_cache.rs

@@ -26,6 +26,32 @@ struct ReadOnlyAccountCacheEntry {
     index: AtomicU32, // Index of the entry in the eviction queue.
 }
 
+#[derive(Default, Debug)]
+struct ReadOnlyCacheStats {
+    hits: AtomicU64,
+    misses: AtomicU64,
+    evicts: AtomicU64,
+    load_us: AtomicU64,
+}
+
+impl ReadOnlyCacheStats {
+    fn reset(&self) {
+        self.hits.store(0, Ordering::Relaxed);
+        self.misses.store(0, Ordering::Relaxed);
+        self.evicts.store(0, Ordering::Relaxed);
+        self.load_us.store(0, Ordering::Relaxed);
+    }
+
+    fn get_and_reset_stats(&self) -> (u64, u64, u64, u64) {
+        let hits = self.hits.swap(0, Ordering::Relaxed);
+        let misses = self.misses.swap(0, Ordering::Relaxed);
+        let evicts = self.evicts.swap(0, Ordering::Relaxed);
+        let load_us = self.load_us.swap(0, Ordering::Relaxed);
+
+        (hits, misses, evicts, load_us)
+    }
+}
+
 #[derive(Debug)]
 pub struct ReadOnlyAccountsCache {
     cache: DashMap<ReadOnlyCacheKey, ReadOnlyAccountCacheEntry>,
@@ -37,10 +63,9 @@ pub struct ReadOnlyAccountsCache {
     queue: Mutex<IndexList<ReadOnlyCacheKey>>,
     max_data_size: usize,
     data_size: AtomicUsize,
-    hits: AtomicU64,
-    misses: AtomicU64,
-    evicts: AtomicU64,
-    load_us: AtomicU64,
+
+    // Performance statistics
+    stats: ReadOnlyCacheStats,
 }
 
 impl ReadOnlyAccountsCache {
@@ -50,10 +75,7 @@ impl ReadOnlyAccountsCache {
             cache: DashMap::default(),
             queue: Mutex::<IndexList<ReadOnlyCacheKey>>::default(),
             data_size: AtomicUsize::default(),
-            hits: AtomicU64::default(),
-            misses: AtomicU64::default(),
-            evicts: AtomicU64::default(),
-            load_us: AtomicU64::default(),
+            stats: ReadOnlyCacheStats::default(),
         }
     }
 
@@ -63,10 +85,7 @@ impl ReadOnlyAccountsCache {
         self.cache.clear();
         self.queue.lock().unwrap().clear();
         self.data_size.store(0, Ordering::Relaxed);
-        self.hits.store(0, Ordering::Relaxed);
-        self.misses.store(0, Ordering::Relaxed);
-        self.evicts.store(0, Ordering::Relaxed);
-        self.load_us.store(0, Ordering::Relaxed);
+        self.stats.reset();
     }
 
     /// true if pubkey is in cache at slot
@@ -78,7 +97,7 @@ impl ReadOnlyAccountsCache {
         let (account, load_us) = measure_us!({
             let key = (pubkey, slot);
             let Some(entry) = self.cache.get(&key) else {
-                self.misses.fetch_add(1, Ordering::Relaxed);
+                self.stats.misses.fetch_add(1, Ordering::Relaxed);
                 return None;
             };
             // Move the entry to the end of the queue.
@@ -91,10 +110,10 @@ impl ReadOnlyAccountsCache {
             }
             let account = entry.account.clone();
             drop(entry);
-            self.hits.fetch_add(1, Ordering::Relaxed);
+            self.stats.hits.fetch_add(1, Ordering::Relaxed);
             Some(account)
         });
-        self.load_us.fetch_add(load_us, Ordering::Relaxed);
+        self.stats.load_us.fetch_add(load_us, Ordering::Relaxed);
         account
     }
 
@@ -135,7 +154,7 @@ impl ReadOnlyAccountsCache {
             num_evicts += 1;
             self.remove(pubkey, slot);
         }
-        self.evicts.fetch_add(num_evicts, Ordering::Relaxed);
+        self.stats.evicts.fetch_add(num_evicts, Ordering::Relaxed);
     }
 
     pub fn remove(&self, pubkey: Pubkey, slot: Slot) -> Option<AccountSharedData> {
@@ -158,12 +177,7 @@ impl ReadOnlyAccountsCache {
     }
 
     pub(crate) fn get_and_reset_stats(&self) -> (u64, u64, u64, u64) {
-        let hits = self.hits.swap(0, Ordering::Relaxed);
-        let misses = self.misses.swap(0, Ordering::Relaxed);
-        let evicts = self.evicts.swap(0, Ordering::Relaxed);
-        let load_us = self.load_us.swap(0, Ordering::Relaxed);
-
-        (hits, misses, evicts, load_us)
+        self.stats.get_and_reset_stats()
     }
 }