diff --git a/clang-tools-extra/clangd/TUScheduler.cpp b/clang-tools-extra/clangd/TUScheduler.cpp
--- a/clang-tools-extra/clangd/TUScheduler.cpp
+++ b/clang-tools-extra/clangd/TUScheduler.cpp
@@ -143,10 +143,14 @@
   /// the cache anymore. If nullptr was cached for \p K, this function will
   /// return a null unique_ptr wrapped into an optional.
   llvm::Optional<std::unique_ptr<ParsedAST>> take(Key K) {
+    trace::Span Span("ASTCache");
     std::unique_lock<std::mutex> Lock(Mut);
     auto Existing = findByKey(K);
-    if (Existing == LRU.end())
+    if (Existing == LRU.end()) {
+      SPAN_ATTACH(Span, "Hit", false);
       return None;
+    }
+    SPAN_ATTACH(Span, "Hit", true);
     std::unique_ptr<ParsedAST> V = std::move(Existing->second);
     LRU.erase(Existing);
     // GCC 4.8 fails to compile `return V;`, as it tries to call the copy