diff --git a/core/trino-main/src/main/java/io/trino/execution/executor/PrioritizedSplitRunner.java b/core/trino-main/src/main/java/io/trino/execution/executor/PrioritizedSplitRunner.java
index 5b98af62e0a3..6d4fb2c76c28 100644
--- a/core/trino-main/src/main/java/io/trino/execution/executor/PrioritizedSplitRunner.java
+++ b/core/trino-main/src/main/java/io/trino/execution/executor/PrioritizedSplitRunner.java
@@ -33,7 +33,7 @@
 import static java.util.Objects.requireNonNull;
 import static java.util.concurrent.TimeUnit.NANOSECONDS;
 
-public class PrioritizedSplitRunner
+public final class PrioritizedSplitRunner
         implements Comparable<PrioritizedSplitRunner>
 {
     private static final AtomicLong NEXT_WORKER_ID = new AtomicLong();
@@ -56,9 +56,8 @@ public class PrioritizedSplitRunner
 
     private final AtomicBoolean destroyed = new AtomicBoolean();
 
-    protected final AtomicReference<Priority> priority = new AtomicReference<>(new Priority(0, 0));
+    private final AtomicReference<Priority> priority = new AtomicReference<>(new Priority(0, 0));
 
-    protected final AtomicLong lastRun = new AtomicLong();
     private final AtomicLong lastReady = new AtomicLong();
     private final AtomicLong start = new AtomicLong();
 
@@ -92,7 +91,7 @@ public class PrioritizedSplitRunner
         this.blockedQuantaWallTime = requireNonNull(blockedQuantaWallTime, "blockedQuantaWallTime is null");
         this.unblockedQuantaWallTime = requireNonNull(unblockedQuantaWallTime, "unblockedQuantaWallTime is null");
 
-        this.updateLevelPriority();
+        updateLevelPriority();
     }
 
     public TaskHandle getTaskHandle()
@@ -165,12 +164,10 @@ public ListenableFuture<Void> process()
             ListenableFuture<Void> blocked = split.processFor(SPLIT_RUN_QUANTA);
             CpuTimer.CpuDuration elapsed = timer.elapsedTime();
 
-            long endNanos = ticker.read();
-            long quantaScheduledNanos = endNanos - startNanos;
+            long quantaScheduledNanos = elapsed.getWall().roundTo(NANOSECONDS);
             scheduledNanos.addAndGet(quantaScheduledNanos);
 
             priority.set(taskHandle.addScheduledNanos(quantaScheduledNanos));
-            lastRun.set(endNanos);
 
             if (blocked == NOT_BLOCKED) {
                 unblockedQuantaWallTime.add(elapsed.getWall());