report udp stats from validator (backport #20587) (#20799)

* report udp stats from validator (#20587)

(cherry picked from commit 4cac66244d)

# Conflicts:
#	core/src/validator.rs

* resolve merge conflicts

Co-authored-by: Jeff Biseda <jbiseda@gmail.com>

core/src/validator.rs

@@ -14,6 +14,7 @@ use {
         serve_repair_service::ServeRepairService,
         sigverify,
         snapshot_packager_service::{PendingSnapshotPackage, SnapshotPackagerService},
+        system_monitor_service::{verify_udp_stats_access, SystemMonitorService},
         tpu::{Tpu, DEFAULT_TPU_COALESCE_MS},
         tvu::{Sockets, Tvu, TvuConfig},
     },
@@ -262,6 +263,7 @@ pub struct Validator {
     transaction_status_service: Option<TransactionStatusService>,
     rewards_recorder_service: Option<RewardsRecorderService>,
     cache_block_meta_service: Option<CacheBlockMetaService>,
+    system_monitor_service: Option<SystemMonitorService>,
     sample_performance_service: Option<SamplePerformanceService>,
     gossip_service: GossipService,
     serve_repair_service: ServeRepairService,
@@ -430,6 +432,12 @@ impl Validator {
 
         *start_progress.write().unwrap() = ValidatorStartProgress::StartingServices;
 
+        verify_udp_stats_access().unwrap_or_else(|err| {
+            error!("Failed to access UDP stats: {}", err);
+            abort();
+        });
+        let system_monitor_service = Some(SystemMonitorService::new(Arc::clone(&exit)));
+
         let leader_schedule_cache = Arc::new(leader_schedule_cache);
         let bank = bank_forks.working_bank();
         if let Some(ref shrink_paths) = config.account_shrink_paths {
@@ -841,6 +849,7 @@ impl Validator {
             transaction_status_service,
             rewards_recorder_service,
             cache_block_meta_service,
+            system_monitor_service,
             sample_performance_service,
             snapshot_packager_service,
             completed_data_sets_service,
@@ -931,6 +940,12 @@ impl Validator {
                 .expect("cache_block_meta_service");
         }
 
+        if let Some(system_monitor_service) = self.system_monitor_service {
+            system_monitor_service
+                .join()
+                .expect("system_monitor_service");
+        }
+
         if let Some(sample_performance_service) = self.sample_performance_service {
             sample_performance_service
                 .join()