diff --git a/perf/benchmark-subset.cc b/perf/benchmark-subset.cc
index 2b40846dc..c35f1109d 100644
--- a/perf/benchmark-subset.cc
+++ b/perf/benchmark-subset.cc
@@ -97,6 +97,40 @@ void AddGlyphs(unsigned num_glyphs_in_font,
   }
 }
 
+// Preprocess face and populate the subset accelerator on it to speed up
+// the subsetting operations.
+static hb_face_t* preprocess_face(hb_face_t* face)
+{
+  hb_subset_input_t* input = hb_subset_input_create_or_fail ();
+
+  hb_set_clear (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
+  hb_set_invert (hb_subset_input_set(input, HB_SUBSET_SETS_UNICODE));
+
+  hb_set_clear (hb_subset_input_set(input,
+                                    HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
+  hb_set_invert (hb_subset_input_set(input,
+                                     HB_SUBSET_SETS_LAYOUT_FEATURE_TAG));
+
+  hb_set_clear (hb_subset_input_set(input,
+                                    HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
+  hb_set_invert (hb_subset_input_set(input,
+                                     HB_SUBSET_SETS_LAYOUT_SCRIPT_TAG));
+
+  hb_set_clear (hb_subset_input_set(input,
+                                    HB_SUBSET_SETS_NAME_ID));
+  hb_set_invert (hb_subset_input_set(input,
+                                     HB_SUBSET_SETS_NAME_ID));
+
+  hb_subset_input_set_flags(input,
+                            HB_SUBSET_FLAGS_ADD_ACCELERATOR_DATA);
+
+  hb_face_t* subset = hb_subset_or_fail (face, input);
+  hb_face_destroy (face);
+  hb_subset_input_destroy (input);
+
+  return subset;
+}
+
 /* benchmark for subsetting a font */
 static void BM_subset (benchmark::State &state,
                        operation_t operation,
@@ -110,6 +144,8 @@ static void BM_subset (benchmark::State &state,
     assert (blob);
     face = hb_face_create (blob, 0);
     hb_blob_destroy (blob);
+
+    face = preprocess_face (face);
   }
 
   hb_subset_input_t* input = hb_subset_input_create_or_fail ();
diff --git a/src/hb-subset.h b/src/hb-subset.h
index ee9187975..9dbe11073 100644
--- a/src/hb-subset.h
+++ b/src/hb-subset.h
@@ -98,8 +98,8 @@ typedef enum { /*< flags >*/
   HB_SUBSET_FLAGS_GLYPH_NAMES =		     0x00000080u,
   HB_SUBSET_FLAGS_NO_PRUNE_UNICODE_RANGES =  0x00000100u,
   HB_SUBSET_FLAGS_ADD_ACCELERATOR_DATA =     0x00000200u,
-  HB_SUBSET_FLAGS_PATCH_MODE =               0x00000400u,
-  HB_SUBSET_FLAGS_OMIT_GLYF =                0x00000800u,
+  // Not supported yet: HB_SUBSET_FLAGS_PATCH_MODE = 0x00000400u,
+  // Not supported yet: HB_SUBSET_FLAGS_OMIT_GLYF =  0x00000800u,
 } hb_subset_flags_t;
 
 /**