Add bench_playback, for quick profiling of SKR playback.

tools/bench_playback.cpp

Index: tools/bench_playback.cpp
diff --git a/tools/bench_playback.cpp b/tools/bench_playback.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..0d00d0a09d3a97f9d2d494de7b6dc105691c12ad
--- /dev/null
+++ b/tools/bench_playback.cpp
@@ -0,0 +1,93 @@
+/*
+ * 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 "SkCommandLineFlags.h"
+#include "SkForceLinking.h"
+#include "SkGraphics.h"
+#include "SkOSFile.h"
+#include "SkPicture.h"
+#include "SkRecordDraw.h"
+#include "SkRecorder.h"
+#include "SkStream.h"
+#include "SkString.h"
+#include "SkTime.h"
+
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+DEFINE_string2(skps, r, "skps", "Directory containing SKPs to read and re-record.");
+DEFINE_int32(loops, 10, "Number of times to play back each SKP.");
+DEFINE_bool(skr, false, "Play via SkRecord instead of SkPicture.");
+DEFINE_int32(tile, 1000000000, "Simulated tile size.");
+
+static void bench(SkPMColor* scratch, SkPicture& src, const char* name) {
+    SkRecord record;
+    SkRecorder recorder(SkRecorder::kWriteOnly_Mode, &record, src.width(), src.height());
+    src.draw(&recorder);
+
+    SkAutoTDelete<SkCanvas> canvas(
+        SkCanvas::NewRasterDirectN32(src.width(), src.height(), scratch, 0));
+    canvas->clipRect(SkRect::MakeWH(FLAGS_tile, FLAGS_tile));
+
+    const SkMSec start = SkTime::GetMSecs();
+    for (int i = 0; i < FLAGS_loops; i++) {
+        if (FLAGS_skr) {
+            SkRecordDraw(record, canvas.get());
+        } else {
+            src.draw(canvas.get());
+        }
+    }
+
+    const SkMSec elapsed = SkTime::GetMSecs() - start;
+    const double msPerLoop = elapsed / (double)FLAGS_loops;
+    printf("%5.1f\t%s\n", msPerLoop, name);
+}
+
+int tool_main(int argc, char** argv);

[f(malita), 2014/04/10 23:27:37]

Is this needed?

[mtklein, 2014/04/11 01:22:35]

Oh, I just realized you might have just meant, is the declaration necessary? 
Some of our compilers will yell at us (correctly but maybe pedantically so) for
defining tool_main before it's been declared.  tool_main, despite the
skia_static_function_style name, is extern, not static.  On iOS builds, it's
called by the real main that lives somewhere else.

+int tool_main(int argc, char** argv) {
+    SkCommandLineFlags::Parse(argc, argv);
+    SkAutoGraphics autoGraphics;
+
+    // We share a single scratch bitmap among benches to reduce the profile noise from allocation.
+    static const int kMaxArea = 209825221;  // tabl_mozilla is this big.
+    SkAutoTMalloc<SkPMColor> scratch(kMaxArea);
+
+    SkOSFile::Iter it(FLAGS_skps[0], ".skp");
+    SkString filename;
+    bool failed = false;
+    while (it.next(&filename)) {
+        const SkString path = SkOSPath::SkPathJoin(FLAGS_skps[0], filename.c_str());
+
+        SkAutoTUnref<SkStream> stream(SkStream::NewFromFile(path.c_str()));
+        if (!stream) {
+            SkDebugf("Could not read %s.\n", path.c_str());
+            failed = true;
+            continue;
+        }
+        SkAutoTUnref<SkPicture> src(SkPicture::CreateFromStream(stream));
+        if (!src) {
+            SkDebugf("Could not read %s as an SkPicture.\n", path.c_str());
+            failed = true;
+            continue;
+        }
+
+        if (src->width() * src->height() > kMaxArea) {
+            SkDebugf("%s (%dx%d) is larger than hardcoded scratch bitmap (%dpx).\n",
+                     path.c_str(), src->width(), src->height(), kMaxArea);
+            failed = true;
+            continue;
+        }
+
+        bench(scratch.get(), *src, filename.c_str());
+    }
+    return failed ? 1 : 0;
+}
+
+#if !defined SK_BUILD_FOR_IOS
+int main(int argc, char * const argv[]) {
+    return tool_main(argc, (char**) argv);
+}
+#endif