diff --git a/graphios.py b/graphios.py
index 222d304..fcacafc 100755
--- a/graphios.py
+++ b/graphios.py
@@ -334,7 +334,8 @@ def process_log(file_name):
                     nobj.UOM = re.sub("[^a-zA-Z]+", "", u)
                     processed_objects.append(nobj)
                 except:
-                    log.critical("failed to parse metric: %s" % nobj.PERFDATA)
+                    log.critical("failed to parse label: '%s' part of perf" \
+                                 "string '%s'" % (metric, nobj.PERFDATA))
                     continue
     return processed_objects