diff --git a/ChangeLog b/ChangeLog
index 93f0fe2853..b978ece075 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+Wed Mar 18 14:13:22 2015  Koichi Sasada  <ko1@atdot.net>
+
+	* benchmark/bm_vm1_gc_wb_ary.rb: run GC to finish "marking" phase.
+
+	* benchmark/bm_vm1_gc_wb_obj.rb: ditto.
+
+	* benchmark/bm_vm1_gc_wb_ary_promoted.rb: add parameter
+	  full_mark: false to invoke only minor GC.
+
+	* benchmark/bm_vm1_gc_wb_obj_promoted.rb: ditto.
+
 Wed Mar 18 12:07:36 2015  Koichi Sasada  <ko1@atdot.net>
 
 	* string.c: add a comment about RSTRING_FSTR.
diff --git a/benchmark/bm_vm1_gc_wb_ary.rb b/benchmark/bm_vm1_gc_wb_ary.rb
index e80538a2da..881528845b 100644
--- a/benchmark/bm_vm1_gc_wb_ary.rb
+++ b/benchmark/bm_vm1_gc_wb_ary.rb
@@ -1,5 +1,9 @@
 short_lived_ary = []
 
+if RUBY_VERSION >= "2.2.0"
+  GC.start(full_mark: false, immediate_mark: true, lazy_sweep: false)
+end
+
 i = 0
 short_lived = ''
 while i<30_000_000 # while loop 1
diff --git a/benchmark/bm_vm1_gc_wb_ary_promoted.rb b/benchmark/bm_vm1_gc_wb_ary_promoted.rb
index 612ec9f888..3c8279c956 100644
--- a/benchmark/bm_vm1_gc_wb_ary_promoted.rb
+++ b/benchmark/bm_vm1_gc_wb_ary_promoted.rb
@@ -1,7 +1,7 @@
 long_lived = []
 
 if RUBY_VERSION > "2.2.0"
-  3.times{ GC.start(immediate_mark: false, lazy_sweep: false) }
+  3.times{ GC.start(full_mark: false, immediate_mark: true, lazy_sweep: false) }
 elsif
   GC.start
 end
diff --git a/benchmark/bm_vm1_gc_wb_obj.rb b/benchmark/bm_vm1_gc_wb_obj.rb
index 9e0aadbbaf..a4067af36b 100644
--- a/benchmark/bm_vm1_gc_wb_obj.rb
+++ b/benchmark/bm_vm1_gc_wb_obj.rb
@@ -3,6 +3,10 @@ class C
 end
 short_lived_obj = C.new
 
+if RUBY_VERSION >= "2.2.0"
+  GC.start(full_mark: false, immediate_mark: true, lazy_sweep: false)
+end
+
 i = 0
 short_lived = ''
 while i<30_000_000 # while loop 1
diff --git a/benchmark/bm_vm1_gc_wb_obj_promoted.rb b/benchmark/bm_vm1_gc_wb_obj_promoted.rb
index 7967e83726..eee07a0248 100644
--- a/benchmark/bm_vm1_gc_wb_obj_promoted.rb
+++ b/benchmark/bm_vm1_gc_wb_obj_promoted.rb
@@ -3,8 +3,8 @@ class C
 end
 long_lived = C.new
 
-if RUBY_VERSION > "2.2.0"
-  3.times{ GC.start(immediate_mark: false, lazy_sweep: false) }
+if RUBY_VERSION >= "2.2.0"
+  3.times{ GC.start(full_mark: false, immediate_mark: true, lazy_sweep: false) }
 elsif
   GC.start
 end