diff --git a/benchmark/mocha.js b/benchmark/mocha.js
index 39912f9..abeae06 100644
--- a/benchmark/mocha.js
+++ b/benchmark/mocha.js
@@ -16,7 +16,7 @@ var Module = require('..')
 
 {
   profile.enabled = true
-  profile('beginning transform')
+  profile('beginning transform without source map')
   var ast = Module.parse(mocha)
   profile('parsed AST')
   ast = Module.transform(ast)
@@ -24,3 +24,18 @@ var Module = require('..')
   recast.print(ast)
   profile('stringified AST')
 }
+
+{
+  profile.enabled = true
+  profile('beginning transform with source map')
+  var ast = Module.parse(mocha, {
+    sourceFileName: 'mocha.js'
+  })
+  profile('parsed AST')
+  ast = Module.transform(ast)
+  profile('transformed AST')
+  recast.print(ast, {
+    sourceMapName: 'mocha.js'
+  })
+  profile('stringified AST')
+}
diff --git a/package.json b/package.json
index 31c234a..41b9598 100644
--- a/package.json
+++ b/package.json
@@ -23,6 +23,7 @@
     "istanbul": "0"
   },
   "scripts": {
+    "bench": "DEBUG=*:profile node benchmark/mocha.js",
     "test": "mocha --reporter spec --bail test/index.js",
     "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot test/index.js",
     "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter dot test/index.js"