--- old/src/share/vm/gc/g1/concurrentMark.cpp	2015-06-23 14:41:46.671441167 +0200
+++ new/src/share/vm/gc/g1/concurrentMark.cpp	2015-06-23 14:41:46.559441171 +0200
@@ -1179,6 +1179,8 @@
 };
 
 void ConcurrentMark::scanRootRegions() {
+  double scan_start = os::elapsedTime();
+
   // Start of concurrent marking.
   ClassLoaderDataGraph::clear_claimed_marks();
 
@@ -1186,6 +1188,11 @@
   // at least one root region to scan. So, if it's false, we
   // should not attempt to do any further work.
   if (root_regions()->scan_in_progress()) {
+    if (G1Log::fine()) {
+      gclog_or_tty->gclog_stamp(concurrent_gc_id());
+      gclog_or_tty->print_cr("[GC concurrent-root-region-scan-start]");
+    }
+
     _parallel_marking_threads = calc_parallel_marking_threads();
     assert(parallel_marking_threads() <= max_parallel_marking_threads(),
            "Maximum number of marking threads exceeded");
@@ -1195,6 +1202,11 @@
     _parallel_workers->set_active_workers(active_workers);
     _parallel_workers->run_task(&task);
 
+    if (G1Log::fine()) {
+      gclog_or_tty->gclog_stamp(concurrent_gc_id());
+      gclog_or_tty->print_cr("[GC concurrent-root-region-scan-end, %1.7lf secs]", os::elapsedTime() - scan_start);
+    }
+
     // It's possible that has_aborted() is true here without actually
     // aborting the survivor scan earlier. This is OK as it's
     // mainly used for sanity checking.
--- old/src/share/vm/gc/g1/concurrentMarkThread.cpp	2015-06-23 14:41:46.931441158 +0200
+++ new/src/share/vm/gc/g1/concurrentMarkThread.cpp	2015-06-23 14:41:46.815441162 +0200
@@ -122,13 +122,8 @@
       // without the root regions have been scanned which would be a
       // correctness issue.
 
-      double scan_start = os::elapsedTime();
       if (!cm()->has_aborted()) {
-        cm_log(G1Log::fine(), false, "[GC concurrent-root-region-scan-start]");
-
         _cm->scanRootRegions();
-
-        cm_log(G1Log::fine(), false, "[GC concurrent-root-region-scan-end, %1.7lf secs]", os::elapsedTime() - scan_start);
       }
 
       double mark_start_sec = os::elapsedTime();