Trace forkSyncStateOnTipPointChange (#1280)

# Description

Trace when forkSyncStateOnTipPointChange completes an iteration.
This provides insight into how much time is spent syncing the mempool
after a new block has been adopted.

ouroboros-consensus/changelog.d/20241011_091242_karl.fb.knutsson_sync_tracing.md

@@ -0,0 +1,4 @@
+### Breaking
+
+- Add TraceMempoolSynced to TraceEventMempool for tracing mempool sync time.
+

ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Mempool/Impl/Common.hs

@@ -56,6 +56,7 @@ import qualified Ouroboros.Consensus.Mempool.TxSeq as TxSeq
 import           Ouroboros.Consensus.Storage.ChainDB (ChainDB)
 import qualified Ouroboros.Consensus.Storage.ChainDB.API as ChainDB
 import           Ouroboros.Consensus.Util (repeatedly)
+import           Ouroboros.Consensus.Util.Enclose (EnclosingTimed)
 import           Ouroboros.Consensus.Util.IOLike hiding (newMVar)
 
 {-------------------------------------------------------------------------------
@@ -556,6 +557,10 @@ data TraceEventMempool blk
       -- transactions.
       MempoolSize
       -- ^ The current size of the Mempool.
+   | TraceMempoolSynced
+      -- ^ Emitted when the mempool is adjusted after the tip has changed.
+      EnclosingTimed
+      -- ^ How long the sync operation took.
 
 deriving instance ( Eq (GenTx blk)
                   , Eq (Validated (GenTx blk))

ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Mempool/Init.hs

@@ -9,6 +9,7 @@ module Ouroboros.Consensus.Mempool.Init (
 
 import           Control.Monad (void)
 import           Control.Tracer
+import           Data.Functor.Contravariant ((>$<))
 import           Ouroboros.Consensus.Block
 import           Ouroboros.Consensus.HeaderValidation
 import           Ouroboros.Consensus.Ledger.Abstract
@@ -18,6 +19,7 @@ import           Ouroboros.Consensus.Mempool.Capacity
 import           Ouroboros.Consensus.Mempool.Impl.Common
 import           Ouroboros.Consensus.Mempool.Query
 import           Ouroboros.Consensus.Mempool.Update
+import           Ouroboros.Consensus.Util.Enclose
 import           Ouroboros.Consensus.Util.IOLike
 import           Ouroboros.Consensus.Util.ResourceRegistry
 import           Ouroboros.Consensus.Util.STM (Watcher (..), forkLinkedWatcher)
@@ -68,7 +70,9 @@ forkSyncStateOnTipPointChange registry menv =
         }
   where
     action :: Point blk -> m ()
-    action _tipPoint = void $ implSyncWithLedger menv
+    action _tipPoint =
+      encloseTimedWith (TraceMempoolSynced >$< mpEnvTracer menv) $
+        void $ implSyncWithLedger menv
 
     -- Using the tip ('Point') allows for quicker equality checks
     getCurrentTip :: STM m (Point blk)