diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java
index 2485bff..75f2681 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java
@@ -15,6 +15,7 @@
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
+import com.google.common.base.Stopwatch;
 import com.google.common.base.Throwables;
 import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
@@ -61,7 +62,6 @@
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadCompatible;
 import com.google.devtools.build.lib.packages.StarlarkSemanticsOptions;
-import com.google.devtools.build.lib.profiler.AutoProfiler;
 import com.google.devtools.build.lib.profiler.Profiler;
 import com.google.devtools.build.lib.profiler.ProfilerTask;
 import com.google.devtools.build.lib.profiler.SilentCloseable;
@@ -88,6 +88,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
+import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
@@ -99,7 +100,6 @@
 import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.TimeUnit;
 import java.util.logging.Logger;
 import javax.annotation.Nullable;
 
@@ -108,6 +108,7 @@
 public class CppCompileAction extends AbstractAction implements IncludeScannable, CommandAction {
 
   private static final Logger logger = Logger.getLogger(CppCompileAction.class.getName());
+  private static final Duration BLOCKED_NESTED_SET_EXPANSION_THRESHOLD = Duration.ofSeconds(5);
   private static final PathFragment BUILD_PATH_FRAGMENT = PathFragment.create("BUILD");
 
   private static final boolean VALIDATION_DEBUG_WARN = false;
@@ -588,19 +589,16 @@
     // used modules. Combining the NestedSets of transitive deps of the top-level modules also
     // gives us an effective way to compute and store discoveredModules.
     Set<Artifact> topLevel = new LinkedHashSet<>(usedModules);
-    try (AutoProfiler ignored =
-        AutoProfiler.logged("nested set expansion", logger, TimeUnit.SECONDS.toMillis(5))) {
-      for (NestedSet<? extends Artifact> transitive : transitivelyUsedModules.values()) {
-        // It is better to iterate over each nested set here instead of creating a joint one and
-        // iterating over it, as this makes use of NestedSet's memoization (each of them has likely
-        // been iterated over before). Don't use Set.removeAll() here as that iterates over the
-        // smaller set (topLevel, which would support efficient lookup) and looks up in the larger
-        // one (transitive, which is a linear scan).
-        // We get a collection view of the NestedSet in a way that can throw an InterruptedException
-        // because a NestedSet may contain a future.
-        for (Artifact module : transitive.toListInterruptibly()) {
-          topLevel.remove(module);
-        }
+    for (NestedSet<? extends Artifact> transitive : transitivelyUsedModules.values()) {
+      // It is better to iterate over each nested set here instead of creating a joint one and
+      // iterating over it, as this makes use of NestedSet's memoization (each of them has likely
+      // been iterated over before). Don't use Set.removeAll() here as that iterates over the
+      // smaller set (topLevel, which would support efficient lookup) and looks up in the larger one
+      // (transitive, which is a linear scan).
+      // We get a collection view of the NestedSet in a way that can throw an InterruptedException
+      // because a NestedSet may contain a future.
+      for (Artifact module : modulesToListInterruptibly(transitive)) {
+        topLevel.remove(module);
       }
     }
     NestedSetBuilder<Artifact> topLevelModulesBuilder = NestedSetBuilder.stableOrder();
@@ -622,6 +620,20 @@
     return additionalInputs;
   }
 
+  private static ImmutableList<? extends Artifact> modulesToListInterruptibly(
+      NestedSet<? extends Artifact> nestedSet) throws InterruptedException {
+    Stopwatch blockedStopwatch = Stopwatch.createStarted();
+    ImmutableList<? extends Artifact> modules = nestedSet.toListInterruptibly();
+    Duration blockedDuration = blockedStopwatch.elapsed();
+    if (BLOCKED_NESTED_SET_EXPANSION_THRESHOLD.compareTo(blockedDuration) < 0) {
+      logger.info(
+          String.format(
+              "Spent %d milliseconds doing nested set expansion, %d elements",
+              blockedDuration.toMillis(), modules.size()));
+    }
+    return modules;
+  }
+
   @Override
   public Artifact getPrimaryInput() {
     return getSourceFile();