diff --git a/lib/config/utils.ts b/lib/config/utils.ts
index ce45ce20cd..e6aa51c7f2 100644
--- a/lib/config/utils.ts
+++ b/lib/config/utils.ts
@@ -1,3 +1,4 @@
+import { instrument } from '../instrumentation/index.ts';
 import { logger } from '../logger/index.ts';
 import { clone } from '../util/clone.ts';
 import { getHighestVulnerabilitySeverity } from '../util/vulnerability/utils.ts';
@@ -8,50 +9,52 @@ export function mergeChildConfig<
   T extends Record<string, any>,
   TChild extends Record<string, any> | undefined,
 >(parent: T, child: TChild): T & TChild {
-  logger.trace({ parent, child }, `mergeChildConfig`);
-  if (!child) {
-    return parent as never;
-  }
-  const parentConfig = clone(parent);
-  const childConfig = clone(child);
-  const config: Record<string, any> = { ...parentConfig, ...childConfig };
+  return instrument('mergeChildConfig', () => {
+    logger.trace({ parent, child }, `mergeChildConfig`);
+    if (!child) {
+      return parent as never;
+    }
+    const parentConfig = clone(parent);
+    const childConfig = clone(child);
+    const config: Record<string, any> = { ...parentConfig, ...childConfig };
 
-  // Ensure highest severity survives parent / child merge
-  if (config?.isVulnerabilityAlert) {
-    config.vulnerabilitySeverity = getHighestVulnerabilitySeverity(
-      parent,
-      child,
-    );
-  }
-
-  for (const option of options.getOptions()) {
-    if (
-      option.mergeable &&
-      childConfig[option.name] &&
-      parentConfig[option.name]
-    ) {
-      logger.trace(`mergeable option: ${option.name}`);
-
-      if (option.name === 'constraints') {
-        config[option.name] = {
-          ...parentConfig[option.name],
-          ...childConfig[option.name],
-        };
-      } else if (option.type === 'array') {
-        config[option.name] = (parentConfig[option.name] as unknown[]).concat(
-          config[option.name],
-        );
-      } else {
-        config[option.name] = mergeChildConfig(
-          parentConfig[option.name] as RenovateConfig,
-          childConfig[option.name] as RenovateConfig,
-        );
-      }
-      logger.trace(
-        { result: config[option.name] },
-        `Merged config.${option.name}`,
+    // Ensure highest severity survives parent / child merge
+    if (config?.isVulnerabilityAlert) {
+      config.vulnerabilitySeverity = getHighestVulnerabilitySeverity(
+        parent,
+        child,
       );
     }
-  }
-  return { ...config, ...config.force };
+
+    for (const option of options.getOptions()) {
+      if (
+        option.mergeable &&
+        childConfig[option.name] &&
+        parentConfig[option.name]
+      ) {
+        logger.trace(`mergeable option: ${option.name}`);
+
+        if (option.name === 'constraints') {
+          config[option.name] = {
+            ...parentConfig[option.name],
+            ...childConfig[option.name],
+          };
+        } else if (option.type === 'array') {
+          config[option.name] = (parentConfig[option.name] as unknown[]).concat(
+            config[option.name],
+          );
+        } else {
+          config[option.name] = mergeChildConfig(
+            parentConfig[option.name] as RenovateConfig,
+            childConfig[option.name] as RenovateConfig,
+          );
+        }
+        logger.trace(
+          { result: config[option.name] },
+          `Merged config.${option.name}`,
+        );
+      }
+    }
+    return { ...config, ...config.force };
+  });
 }