--- old/src/share/vm/gc/g1/concurrentMark.cpp	2016-01-27 14:54:08.609193957 -0500
+++ new/src/share/vm/gc/g1/concurrentMark.cpp	2016-01-27 14:54:08.021160597 -0500
@@ -488,11 +488,11 @@
     double overall_cm_overhead =
       (double) MaxGCPauseMillis * marking_overhead /
       (double) GCPauseIntervalMillis;
-    double cpu_ratio = 1.0 / (double) os::processor_count();
+    double cpu_ratio = 1.0 / (double) os::active_processor_count();
     double marking_thread_num = ceil(overall_cm_overhead / cpu_ratio);
     double marking_task_overhead =
       overall_cm_overhead / marking_thread_num *
-                                              (double) os::processor_count();
+                                              (double) os::active_processor_count();
     double sleep_factor =
                        (1.0 - marking_task_overhead) / marking_task_overhead;