Measure frame decodes more accurately from ImageDecodeBench

third_party/WebKit/Source/platform/testing/ImageDecodeBench.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Provides a minimal wrapping of the Blink image decoders. Used to perform
 // a non-threaded, memory-to-memory image decode using micro second accuracy
 // clocks to measure image decode time. Optionally applies color correction
 // during image decoding on supported platforms (default off). Usage:
 //
 //   % ninja -C out/Release image_decode_bench &&
 //      ./out/Release/image_decode_bench file [iterations]
 //
+// The output is formatted for use in a .csv file (comma-separated variable).
+// Each row represents successive frames in an animated image.
+// (frame 1, frame 2, frame 3...)
+// Each column represents a successive iteration of decoding the whole animated

[scroggo_chromium, 2017/05/23 21:04:23]

You said you would change this to "Each column represents a single frame decoded
from successive iterations." Is that in a forth-coming patch?

[cblume, 2017/05/23 21:42:06]

Oops. Done.

+// image.
+// Iteration 1: (frame 1, frame 2, frame 3...)

[scroggo_chromium, 2017/05/23 21:04:23]

nit: I think in zero-based indices.

[cblume, 2017/05/23 21:42:07]

Done.

+// Iteration 2: (frame 1, frame 2, frame 3...)
+//
+// This means non-animated images will show up as one column.
+//
+// The output of this program can be saved to a .csv file, which can then be
+// imported into Google Sheets. From Sheets, the user can create graphs to

[scroggo_chromium, 2017/05/23 21:04:23]

Sorry, I should've been more clear here. We probably don't want to
mention/recommend a Google product. (I'm guessing using some other spreadsheet
program would have similar benefits?)

I was thinking more like specify the types of graph to create, etc. If you think
that's too much detail to provide here, that's fine with me. (And the commands
probably are specific.)

[cblume, 2017/05/23 21:42:07]

Oh, you're right. I definitely don't want Chromium to feel like it excludes
non-Google solutions.

I've changed the wording around in a way that I think might be more clear.

+// visualize the decode times of a given frame and trim noise as appropriate.
+//
+// Each frame is different and so comparing separate frames may not be fruitful.
+// For example, frame 1 may cover a large area and require more time to decode.
+// Frame 2 may have a small rect and be faster to decode.
+//
 // TODO(noel): Consider adding md5 checksum support to WTF. Use it to compute
 // the decoded image frame md5 and output that value.
 //
 // TODO(noel): Consider integrating this tool in Chrome telemetry for realz,
 // using the image corpii used to assess Blink image decode performance. Refer
 // to http://crbug.com/398235#c103 and http://crbug.com/258324#c5
 
 #include <memory>
+#include <vector>
 #include "base/command_line.h"
 #include "platform/SharedBuffer.h"
 #include "platform/image-decoders/ImageDecoder.h"
 #include "platform/wtf/PassRefPtr.h"
 #include "platform/wtf/PtrUtil.h"
 #include "public/platform/Platform.h"
 #include "ui/gfx/test/icc_profiles.h"
 
 #if defined(_WIN32)
 #include <mmsystem.h>
@@ skipping 166 matching lines @@
       WrapArrayUnique(new unsigned char[file_size]);
   if (file_size != fread(buffer.get(), 1, file_size, fp)) {
     fprintf(stderr, "Error reading file %s\n", file_name);
     exit(2);
   }
 
   fclose(fp);
   return SharedBuffer::Create(buffer.get(), file_size);
 }
 
-bool DecodeImageData(SharedBuffer* data,
-                     bool color_correction,
-                     size_t packet_size) {
-  std::unique_ptr<ImageDecoder> decoder = ImageDecoder::Create(
-      data, true, ImageDecoder::kAlphaPremultiplied,
-      color_correction ? ColorBehavior::TransformToTargetForTesting()
-                       : ColorBehavior::Ignore());
-  if (!packet_size) {
-    bool all_data_received = true;
-    decoder->SetData(data, all_data_received);
+// This vector represents a single iteration of one (possibly animated) image.
+// Each entry is a single timing of a single frame.
+using FrameTimings = std::vector<double>;
+using IterationsOfFrameTimings = std::vector<FrameTimings>;
 
-    int frame_count = decoder->FrameCount();
-    for (int i = 0; i < frame_count; ++i) {
-      if (!decoder->FrameBufferAtIndex(i))
-        return false;
+void Print2DResults(const IterationsOfFrameTimings& timings) {
+  for (const FrameTimings& iteration : timings) {
+    for (double frame_time : iteration) {
+      printf("%f,", frame_time);
     }
+    printf("\n");
+  }
+  printf("\n");
+}
 
-    return !decoder->Failed();
+void TimeDecode(ImageDecoder* decoder,
+                PassRefPtr<SharedBuffer> data,
+                size_t iterations) {
+  bool all_data_received = true;
+  decoder->SetData(data.Get(), all_data_received);
+
+  size_t frame_count = decoder->FrameCount();
+
+  IterationsOfFrameTimings timings(iterations, FrameTimings(frame_count, 0.0));
+
+  for (size_t i = 0; i < iterations; ++i) {
+    for (size_t frame_index = 0; frame_index < frame_count; ++frame_index) {
+      double start_time = GetCurrentTime();
+      ImageFrame* frame = decoder->FrameBufferAtIndex(frame_index);
+      double elapsed_time = GetCurrentTime() - start_time;
+      if (frame->GetStatus() != ImageFrame::kFrameComplete) {
+        fprintf(stderr, "Image decode failed\n");
+        exit(3);
+      }
+      timings[i][frame_index] = elapsed_time;
+    }
   }
 
+  Print2DResults(timings);
+}
+
+// This function mimics deferred decoding in Chromium when not all data has been
+// received yet.
+void TimePacketedDecode(ImageDecoder* decoder,
+                        PassRefPtr<SharedBuffer> data,
+                        size_t packet_size,
+                        size_t iterations) {
+  // Find total frame count.
+  // Doing this requires a decoder with full data (no packet size).
+  std::unique_ptr<ImageDecoder> frame_count_decoder =
+      ImageDecoder::Create(data.Get(), true, ImageDecoder::kAlphaPremultiplied,
+                           ColorBehavior::Ignore());
+
+  constexpr bool total_all_data_received = true;
+  frame_count_decoder->SetData(data.Get(), total_all_data_received);
+  size_t total_frame_count = frame_count_decoder->FrameCount();
+
+  IterationsOfFrameTimings timings(iterations,
+                                   FrameTimings(total_frame_count, 0.0));
+
   RefPtr<SharedBuffer> packet_data = SharedBuffer::Create();
   size_t position = 0;
   size_t next_frame_to_decode = 0;
   while (true) {
     const char* packet;
     size_t length = data->GetSomeData(packet, position);
 
     length = std::min(length, packet_size);
     packet_data->Append(packet, length);
     position += length;
 
     bool all_data_received = position == data->size();
     decoder->SetData(packet_data.Get(), all_data_received);
 
     size_t frame_count = decoder->FrameCount();
-    for (; next_frame_to_decode < frame_count; ++next_frame_to_decode) {
-      ImageFrame* frame = decoder->FrameBufferAtIndex(next_frame_to_decode);
-      if (frame->GetStatus() != ImageFrame::kFrameComplete)
-        break;
+    for (size_t i = 0; i < iterations; ++i) {
+      for (; next_frame_to_decode < frame_count; ++next_frame_to_decode) {
+        double start_time = GetCurrentTime();
+        ImageFrame* frame = decoder->FrameBufferAtIndex(next_frame_to_decode);
+        double elapsed_time = GetCurrentTime() - start_time;
+        if (frame->GetStatus() != ImageFrame::kFrameComplete) {
+          fprintf(stderr, "Image decode failed\n");
+          exit(3);
+        }
+        timings[i][next_frame_to_decode] = elapsed_time;
+      }
     }
 
-    if (all_data_received || decoder->Failed())
-      break;
+    if (all_data_received || decoder->Failed()) {
+      fprintf(stderr, "Image decode failed\n");
+      exit(3);
+    }
   }
 
-  return !decoder->Failed();
+  Print2DResults(timings);
 }
 
 }  // namespace
 
 int Main(int argc, char* argv[]) {
   base::CommandLine::Init(argc, argv);
 
   // If the platform supports color correction, allow it to be controlled.
 
   bool apply_color_correction = false;
-
   if (argc >= 2 && strcmp(argv[1], "--color-correct") == 0) {
-    apply_color_correction = (--argc, ++argv, true);
+    --argc;
+    ++argv;
+    apply_color_correction = true;
     gfx::ICCProfile profile = gfx::ICCProfileForTestingColorSpin();
     ColorBehavior::SetGlobalTargetColorProfile(profile);
   }
 
   if (argc < 2) {
     fprintf(stderr,
             "Usage: %s [--color-correct] file [iterations] [packetSize]\n",
             argv[0]);
     exit(1);
   }
@@ skipping 38 matching lines @@
   // segments into one, contiguous block of memory.
 
   RefPtr<SharedBuffer> data = ReadFile(argv[1]);
   if (!data.Get() || !data->size()) {
     fprintf(stderr, "Error reading image data from [%s]\n", argv[1]);
     exit(2);
   }
 
   data->Data();
 
-  // Warm-up: throw out the first iteration for more consistent results.
+  // Image decode bench for iterations.
 
-  if (!DecodeImageData(data.Get(), apply_color_correction, packet_size)) {
-    fprintf(stderr, "Image decode failed [%s]\n", argv[1]);
-    exit(3);
+  std::unique_ptr<ImageDecoder> decoder = ImageDecoder::Create(
+      data, true, ImageDecoder::kAlphaPremultiplied,
+      apply_color_correction ? ColorBehavior::TransformToTargetForTesting()
+                             : ColorBehavior::Ignore());
+  if (packet_size) {
+    TimePacketedDecode(decoder.get(), data.Get(), packet_size, iterations);
+  } else {
+    TimeDecode(decoder.get(), data.Get(), iterations);
   }
 
-  // Image decode bench for iterations.
-
-  double total_time = 0.0;
-
-  for (size_t i = 0; i < iterations; ++i) {
-    double start_time = GetCurrentTime();
-    bool decoded =
-        DecodeImageData(data.Get(), apply_color_correction, packet_size);
-    double elapsed_time = GetCurrentTime() - start_time;
-    total_time += elapsed_time;
-    if (!decoded) {
-      fprintf(stderr, "Image decode failed [%s]\n", argv[1]);
-      exit(3);
-    }
-  }
-
-  // Results to stdout.
-
-  double average_time = total_time / static_cast<double>(iterations);
-  printf("%f %f\n", total_time, average_time);
   return 0;
 }
 
 }  // namespace blink
 
 int main(int argc, char* argv[]) {
   return blink::Main(argc, argv);
 }