Add nanobench, a fresh look at our microbenchmark harness.
out/Release/nanobench runs 4-5x faster on my Z620 and ~2x faster on my N5 than out/Release/bench with the same configs.
(Debug isn't really comparable. I haven't added the Debug -> single loop check.)
BUG=skia:
R=djsollen@google.com, mtklein@google.com
Author: mtklein@chromium.org
Review URL: https://codereview.chromium.org/347443002
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
new file mode 100644
index 0000000..77df430
--- /dev/null
+++ b/bench/nanobench.cpp
@@ -0,0 +1,203 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Benchmark.h"
+#include "CrashHandler.h"
+#include "Stats.h"
+#include "Timer.h"
+
+#include "SkCanvas.h"
+#include "SkCommandLineFlags.h"
+#include "SkForceLinking.h"
+#include "SkGraphics.h"
+#include "SkString.h"
+#include "SkSurface.h"
+
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+DEFINE_int32(samples, 10, "Number of samples to measure for each bench.");
+DEFINE_int32(overheadLoops, 100000, "Loops to estimate timer overhead.");
+DEFINE_double(overheadGoal, 0.0001,
+ "Loop until timer overhead is at most this fraction of our measurments.");
+DEFINE_string(match, "", "The usual filters on file names of benchmarks to measure.");
+DEFINE_bool2(quiet, q, false, "Print only bench name and minimum sample.");
+DEFINE_bool2(verbose, v, false, "Print all samples.");
+DEFINE_string(config, "8888 nonrendering",
+ "Configs to measure. Options: 565 8888 nonrendering");
+
+// TODO: GPU benches
+
+static SkString humanize(double ms) {
+ if (ms > 1e+3) return SkStringPrintf("%.3gs", ms/1e3);
+ if (ms < 1e-3) return SkStringPrintf("%.3gns", ms*1e6);
+ if (ms < 1) return SkStringPrintf("%.3gµs", ms*1e3);
+ return SkStringPrintf("%.3gms", ms);
+}
+
+static double estimate_timer_overhead() {
+ double overhead = 0;
+ WallTimer timer;
+ for (int i = 0; i < FLAGS_overheadLoops; i++) {
+ timer.start();
+ timer.end();
+ overhead += timer.fWall;
+ }
+ return overhead / FLAGS_overheadLoops;
+}
+
+static void safe_flush(SkCanvas* canvas) {
+ if (canvas) {
+ canvas->flush();
+ }
+}
+
+static int guess_loops(double overhead, Benchmark* bench, SkCanvas* canvas) {
+ WallTimer timer;
+
+ // Measure timer overhead and bench time together.
+ do {
+ timer.start();
+ bench->draw(1, canvas);
+ safe_flush(canvas);
+ timer.end();
+ } while (timer.fWall < overhead); // Shouldn't normally happen.
+
+ // Later we'll just start and stop the timer once, but loop N times.
+ // We'll pick N to make timer overhead negligible:
+ //
+ // Timer Overhead
+ // ------------------------------- < FLAGS_overheadGoal
+ // Timer Overhead + N * Bench Time
+ //
+ // where timer.fWall ≈ Timer Overhead + Bench Time.
+ //
+ // Doing some math, we get:
+ //
+ // (Timer Overhead / FLAGS_overheadGoal) - Timer Overhead
+ // ----------------------------------------------------- < N
+ // (timer.fWall - Timer Overhead)
+ //
+ // Luckily, this also works well in practice. :)
+ const double numer = overhead / FLAGS_overheadGoal - overhead;
+ const double denom = timer.fWall - overhead;
+ return (int)ceil(numer / denom);
+}
+
+static bool push_config_if_enabled(const char* config, SkTDArray<const char*>* configs) {
+ if (FLAGS_config.contains(config)) {
+ configs->push(config);
+ return true;
+ }
+ return false;
+}
+
+static void create_surfaces(Benchmark* bench,
+ SkTDArray<SkSurface*>* surfaces,
+ SkTDArray<const char*>* configs) {
+
+ if (bench->isSuitableFor(Benchmark::kNonRendering_Backend)
+ && push_config_if_enabled("nonrendering", configs)) {
+ surfaces->push(NULL);
+ }
+
+ if (bench->isSuitableFor(Benchmark::kRaster_Backend)) {
+ const int w = bench->getSize().fX,
+ h = bench->getSize().fY;
+
+ if (push_config_if_enabled("8888", configs)) {
+ const SkImageInfo info = { w, h, kN32_SkColorType, kPremul_SkAlphaType };
+ surfaces->push(SkSurface::NewRaster(info));
+ }
+
+ if (push_config_if_enabled("565", configs)) {
+ const SkImageInfo info = { w, h, kRGB_565_SkColorType, kOpaque_SkAlphaType };
+ surfaces->push(SkSurface::NewRaster(info));
+ }
+ }
+}
+
+int tool_main(int argc, char** argv);
+int tool_main(int argc, char** argv) {
+ SetupCrashHandler();
+ SkAutoGraphics ag;
+ SkCommandLineFlags::Parse(argc, argv);
+
+ const double overhead = estimate_timer_overhead();
+
+ if (FLAGS_verbose) {
+ // No header.
+ } else if (FLAGS_quiet) {
+ SkDebugf("min\tbench\tconfig\n");
+ } else {
+ SkDebugf("loops\tmin\tmean\tmax\tstddev\tbench\tconfig\n");
+ }
+
+ for (const BenchRegistry* r = BenchRegistry::Head(); r != NULL; r = r->next()) {
+ SkAutoTDelete<Benchmark> bench(r->factory()(NULL));
+ if (SkCommandLineFlags::ShouldSkip(FLAGS_match, bench->getName())) {
+ continue;
+ }
+
+ SkTDArray<SkSurface*> surfaces;
+ SkTDArray<const char*> configs;
+ create_surfaces(bench.get(), &surfaces, &configs);
+
+ bench->preDraw();
+ for (int j = 0; j < surfaces.count(); j++) {
+ SkCanvas* canvas = surfaces[j] ? surfaces[j]->getCanvas() : NULL;
+ const char* config = configs[j];
+
+ bench->draw(1, canvas); // Just paranoid warmup.
+ safe_flush(canvas);
+ const int loops = guess_loops(overhead, bench.get(), canvas);
+
+ SkAutoTMalloc<double> samples(FLAGS_samples);
+ WallTimer timer;
+ for (int i = 0; i < FLAGS_samples; i++) {
+ timer.start();
+ bench->draw(loops, canvas);
+ safe_flush(canvas);
+ timer.end();
+ samples[i] = timer.fWall / loops;
+ }
+
+ Stats stats(samples.get(), FLAGS_samples);
+
+ if (FLAGS_verbose) {
+ for (int i = 0; i < FLAGS_samples; i++) {
+ SkDebugf("%s ", humanize(samples[i]).c_str());
+ }
+ SkDebugf("%s\n", bench->getName());
+ } else if (FLAGS_quiet) {
+ if (configs.count() == 1) {
+ config = ""; // Only print the config if we run the same bench on more than one.
+ }
+ SkDebugf("%s\t%s\t%s\n", humanize(stats.min).c_str(), bench->getName(), config);
+ } else {
+ const double stddev_percent = 100 * sqrt(stats.var) / stats.mean;
+ SkDebugf("%d\t%s\t%s\t%s\t%.0f%%\t%s\t%s\n"
+ , loops
+ , humanize(stats.min).c_str()
+ , humanize(stats.mean).c_str()
+ , humanize(stats.max).c_str()
+ , stddev_percent
+ , bench->getName()
+ , config
+ );
+ }
+ }
+ surfaces.deleteAll();
+ }
+
+ return 0;
+}
+
+#if !defined SK_BUILD_FOR_IOS
+int main(int argc, char * const argv[]) {
+ return tool_main(argc, (char**) argv);
+}
+#endif