--- old/src/share/vm/gc/shared/generation.cpp	2017-09-01 13:03:03.342353399 +0200
+++ new/src/share/vm/gc/shared/generation.cpp	2017-09-01 13:03:03.206347994 +0200
@@ -94,23 +94,15 @@
               p2i(_virtual_space.high_boundary()));
 }
 
-void Generation::print_summary_info() { print_summary_info_on(tty); }
-
-void Generation::print_summary_info_on(outputStream* st) {
+void Generation::print_summary_info() {
   StatRecord* sr = stat_record();
   double time = sr->accumulated_time.seconds();
-  // I didn't want to change the logging when removing the level concept,
-  // but I guess this logging could say young/old or something instead of 0/1.
-  uint level;
-  if (GenCollectedHeap::heap()->is_young_gen(this)) {
-    level = 0;
-  } else {
-    level = 1;
-  }
-  st->print_cr("[Accumulated GC generation %d time %3.7f secs, "
-               "%u GC's, avg GC time %3.7f]",
-               level, time, sr->invocations,
-               sr->invocations > 0 ? time / sr->invocations : 0.0);
+  log_debug(gc, heap, exit)("Accumulated %s generation GC time %3.7f secs, "
+                            "%u GC's, avg GC time %3.7f",
+                            GenCollectedHeap::heap()->is_young_gen(this) ? "young" : "old" ,
+                            time,
+                            sr->invocations,
+                            sr->invocations > 0 ? time / sr->invocations : 0.0);
 }
 
 // Utility iterator classes