blockstore: Make metrics reporting service more responsive to exit fl…

…ag (solana-labs#3976)

The exit flag may get set when someone wishes to stop their validator.
This service does check if the exit flag has been set, but it only
checks every 10 seconds (the metrics reporting interval).

This change keeps the metrics reporting interval at 10s, but makes the
service check if the exit flag has been set every 1s

ledger/src/blockstore_metric_report_service.rs

@@ -9,14 +9,14 @@ use {
             Arc,
         },
         thread::{self, Builder, JoinHandle},
-        time::Duration,
+        time::{Duration, Instant},
     },
 };
 
 // Determines how often we report blockstore metrics under
 // BlockstoreMetricReportService. Note that there are other blockstore
 // metrics that are reported outside BlockstoreMetricReportService.
-const BLOCKSTORE_METRICS_REPORT_PERIOD_MILLIS: u64 = 10000;
+const BLOCKSTORE_METRICS_REPORT_INTERVAL: Duration = Duration::from_secs(10);
 
 pub struct BlockstoreMetricReportService {
     t_cf_metric: JoinHandle<()>,
@@ -26,15 +26,24 @@ impl BlockstoreMetricReportService {
     pub fn new(blockstore: Arc<Blockstore>, exit: Arc<AtomicBool>) -> Self {
         let t_cf_metric = Builder::new()
             .name("solRocksCfMtrcs".to_string())
-            .spawn(move || loop {
-                if exit.load(Ordering::Relaxed) {
-                    break;
+            .spawn(move || {
+                info!("BlockstoreMetricReportService has started");
+                let mut last_report_time = Instant::now();
+                loop {
+                    if exit.load(Ordering::Relaxed) {
+                        break;
+                    }
+
+                    if last_report_time.elapsed() > BLOCKSTORE_METRICS_REPORT_INTERVAL {
+                        blockstore.submit_rocksdb_cf_metrics_for_all_cfs();
+                        blockstore.report_rpc_api_metrics();
+
+                        last_report_time = Instant::now();
+                    }
+
+                    thread::sleep(Duration::from_secs(1));
                 }
-                thread::sleep(Duration::from_millis(
-                    BLOCKSTORE_METRICS_REPORT_PERIOD_MILLIS,
-                ));
-                blockstore.submit_rocksdb_cf_metrics_for_all_cfs();
-                blockstore.report_rpc_api_metrics();
+                info!("BlockstoreMetricReportService has stopped");
             })
             .unwrap();
         Self { t_cf_metric }