[perf] Start writing subset benchmarks.

perf/benchmark-subset.cc

@@ -0,0 +1,70 @@
+#include "benchmark/benchmark.h"
+
+#include "hb-subset.h"
+
+void AddCodepoints(const hb_set_t* codepoints_in_font,
+                   unsigned subset_size,
+                   hb_subset_input_t* input)
+{
+  hb_codepoint_t cp = HB_SET_VALUE_INVALID;
+  for (unsigned i = 0; i < subset_size; i++) {
+    // TODO(garretrieger): pick randomly.
+    assert (hb_set_next (codepoints_in_font, &cp));
+    hb_set_add (hb_subset_input_unicode_set (input), cp);
+  }
+}
+
+/* benchmark for subsetting a font */
+static void BM_subset_codepoints (benchmark::State &state,
+                                  const char *font_path,
+                                  unsigned subset_size)
+{
+  hb_face_t *face;
+  {
+    hb_blob_t *blob = hb_blob_create_from_file_or_fail (font_path);
+    assert (blob);
+    face = hb_face_create (blob, 0);
+    hb_blob_destroy (blob);
+  }
+
+  hb_subset_input_t* input = hb_subset_input_create_or_fail ();
+  assert (input);
+
+  {
+    hb_set_t* all_codepoints = hb_set_create ();
+    hb_face_collect_unicodes (face, all_codepoints);
+
+    AddCodepoints(all_codepoints, subset_size, input);
+
+    hb_set_destroy (all_codepoints);
+  }
+
+  for (auto _ : state)
+  {
+    hb_face_t* subset = hb_subset_or_fail (face, input);
+    assert (subset);
+    hb_face_destroy (subset);
+  }
+
+  hb_subset_input_destroy (input);
+  hb_face_destroy (face);
+}
+
+// TODO(garretrieger): Use range() for subset size.
+BENCHMARK_CAPTURE (BM_subset_codepoints, subset_roboto_10,
+                   "perf/fonts/Roboto-Regular.ttf", 10)
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_CAPTURE (BM_subset_codepoints, subset_roboto_100,
+                   "perf/fonts/Roboto-Regular.ttf", 100)
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_CAPTURE (BM_subset_codepoints, subset_noto_nastaliq_urdu_10,
+                   "perf/fonts/NotoNastaliqUrdu-Regular.ttf", 10)
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_CAPTURE (BM_subset_codepoints, subset_noto_nastaliq_urdu_100,
+                   "perf/fonts/NotoNastaliqUrdu-Regular.ttf", 100)
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_MAIN();

perf/meson.build

@@ -40,3 +40,13 @@ benchmark('benchmark-map', executable('benchmark-map', 'benchmark-map.cc',
   link_with: [libharfbuzz],
   install: false,
 ), workdir: meson.current_source_dir() / '..', timeout: 100)
+
+benchmark('benchmark-subset', executable('benchmark-subset', 'benchmark-subset.cc',
+  dependencies: [
+    google_benchmark_dep,
+  ],
+  cpp_args: [],
+  include_directories: [incconfig, incsrc],
+  link_with: [libharfbuzz, libharfbuzz_subset],
+  install: false,
+), workdir: meson.current_source_dir() / '..', timeout: 100)