diff --git a/benchmark/farm.py b/benchmark/farm.py
index f606363..e5f8962 100755
--- a/benchmark/farm.py
+++ b/benchmark/farm.py
@@ -288,11 +288,9 @@ def ensureImageOutputDir(results_output_dir):
 
 
 def getResultJSONString(ctx, results):
-    import copy
     # Convert custom classes to dictionaries for easier JSON dump.
-    json_results = copy.deepcopy(results)
-    json_results['schema_version'] = RESULT_JSON_SCHEMA_VERSION
-    stats = json_results['stats']
+    results['schema_version'] = RESULT_JSON_SCHEMA_VERSION
+    stats = results['stats']
     for scene in ctx.scenes:
         if scene not in stats:
             continue
@@ -301,7 +299,7 @@ def getResultJSONString(ctx, results):
             stats[scene]['result'] = 'OK'
         else:
             stats[scene] = {'result': 'CRASH'}
-    return json.dumps(json_results, sort_keys=True, indent=2)
+    return json.dumps(results, sort_keys=True, indent=2)
 
 
 def saveResults(ctx, results, output_dir):