blob: 2308d922a351cf1405d50c2bf88ad3beda17d0f8 [file] [log] [blame]
// Copyright 2017 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.
#include "cc/tiles/checker_image_tracker.h"
#include "base/bind.h"
#include "base/metrics/histogram_macros.h"
#include "base/stl_util.h"
#include "base/trace_event/trace_event.h"
namespace cc {
namespace {
// The enum for recording checker-imaging decision UMA metric. Keep this
// consistent with the ordering in CheckerImagingDecision in enums.xml.
// Note that this enum is used to back a UMA histogram so should be treated as
// append only.
enum class CheckerImagingDecision {
kCanChecker = 0,
// Animation State vetoes.
kVetoedAnimatedImage = 1,
kVetoedVideoFrame = 2,
// TODO(vmpstr): 3 used to be kVetoedAnimationUnknown, remove it somehow?
kVetoedMultipartImage = 4,
// Load state vetoes.
kVetoedPartiallyLoadedImage = 5,
// TODO(vmpstr): 6 used to be kVetoedLoadStateUnknown, remove it somehow?
// Size associated vetoes.
kVetoedSmallerThanCheckeringSize = 7,
kVetoedLargerThanCacheSize = 8,
// Vetoed because checkering of images has been disabled.
kVetoedForceDisable = 9,
// 10 used to be kVetoedNotRequiredForActivation.
// Sync was requested by the embedder.
kVetoedSyncRequested = 11,
std::string ToString(PaintImage::Id paint_image_id,
CheckerImagingDecision decision) {
std::ostringstream str;
str << "paint_image_id[" << paint_image_id << "] decision["
<< static_cast<int>(decision) << "]";
return str.str();
CheckerImagingDecision GetAnimationDecision(const PaintImage& image) {
if (image.is_multipart())
return CheckerImagingDecision::kVetoedMultipartImage;
switch (image.animation_type()) {
case PaintImage::AnimationType::ANIMATED:
return CheckerImagingDecision::kVetoedAnimatedImage;
case PaintImage::AnimationType::VIDEO:
return CheckerImagingDecision::kVetoedVideoFrame;
case PaintImage::AnimationType::STATIC:
return CheckerImagingDecision::kCanChecker;
return CheckerImagingDecision::kCanChecker;
CheckerImagingDecision GetLoadDecision(const PaintImage& image) {
switch (image.completion_state()) {
case PaintImage::CompletionState::DONE:
return CheckerImagingDecision::kCanChecker;
case PaintImage::CompletionState::PARTIALLY_DONE:
return CheckerImagingDecision::kVetoedPartiallyLoadedImage;
return CheckerImagingDecision::kCanChecker;
CheckerImagingDecision GetSizeDecision(const SkIRect& src_rect,
size_t min_bytes,
size_t max_bytes) {
// Ideally we would use the original image rect here to estimate the decode
// duration for this image. But in the case of sprites/atlases, where small
// subsets of this image are used across multiple tiles, re-invalidating for
// replacing these images can incur heavy raster cost. So we use the src_rect
// here instead.
// TODO(khushalsagar): May be we should look at the invalidation rect for an
// image here to detect these cases instead?
base::CheckedNumeric<size_t> checked_size = 4;
checked_size *= src_rect.width();
checked_size *= src_rect.height();
size_t size = checked_size.ValueOrDefault(std::numeric_limits<size_t>::max());
if (size < min_bytes)
return CheckerImagingDecision::kVetoedSmallerThanCheckeringSize;
else if (size > max_bytes)
return CheckerImagingDecision::kVetoedLargerThanCacheSize;
return CheckerImagingDecision::kCanChecker;
CheckerImagingDecision GetCheckerImagingDecision(const PaintImage& image,
const SkIRect& src_rect,
size_t min_bytes,
size_t max_bytes) {
CheckerImagingDecision decision = GetAnimationDecision(image);
if (decision != CheckerImagingDecision::kCanChecker)
return decision;
decision = GetLoadDecision(image);
if (decision != CheckerImagingDecision::kCanChecker)
return decision;
return GetSizeDecision(src_rect, min_bytes, max_bytes);
} // namespace
// static
const int CheckerImageTracker::kNoDecodeAllowedPriority = -1;
PaintImage paint_image,
DecodeType type)
: paint_image(std::move(paint_image)), type(type) {}
CheckerImageTracker::CheckerImageTracker(ImageController* image_controller,
CheckerImageTrackerClient* client,
bool enable_checker_imaging,
size_t min_image_bytes_to_checker)
: image_controller_(image_controller),
weak_factory_(this) {}
CheckerImageTracker::~CheckerImageTracker() = default;
void CheckerImageTracker::SetNoDecodesAllowed() {
decode_priority_allowed_ = kNoDecodeAllowedPriority;
void CheckerImageTracker::SetMaxDecodePriorityAllowed(DecodeType decode_type) {
DCHECK_GT(decode_type, kNoDecodeAllowedPriority);
DCHECK_GE(decode_type, decode_priority_allowed_);
DCHECK_LE(decode_type, DecodeType::kLast);
if (decode_priority_allowed_ == decode_type)
decode_priority_allowed_ = decode_type;
// This will start the next decode if applicable.
void CheckerImageTracker::ScheduleImageDecodeQueue(
ImageDecodeQueue image_decode_queue) {
// The decodes in the queue should be prioritized correctly.
DecodeType type = DecodeType::kRaster;
for (const auto& image_request : image_decode_queue) {
DCHECK_GE(image_request.type, type);
type = image_request.type;
image_decode_queue_ = std::move(image_decode_queue);
const PaintImageIdFlatSet&
CheckerImageTracker::TakeImagesToInvalidateOnSyncTree() {
DCHECK_EQ(invalidated_images_on_current_sync_tree_.size(), 0u)
<< "Sync tree can not be invalidated more than once";
return invalidated_images_on_current_sync_tree_;
void CheckerImageTracker::DidActivateSyncTree() {
for (auto image_id : invalidated_images_on_current_sync_tree_)
void CheckerImageTracker::ClearTracker(bool can_clear_decode_policy_tracking) {
// Unlock all images and tracking for images pending invalidation. The
// |images_invalidated_on_current_sync_tree_| will be cleared when the sync
// tree is activated.
// Note that we assume that any images with DecodePolicy::ASYNC, which may be
// checkered, are safe to stop tracking here and will either be re-checkered
// and invalidated when the decode completes or be invalidated externally.
// This is because the policy decision for checkering an image is based on
// inputs received from a PaintImage in the DisplayItemList. The policy chosen
// for a PaintImage should remain unchanged.
// If the external inputs for deciding the decode policy for an image change,
// they should be accompanied with an invalidation during paint.
if (can_clear_decode_policy_tracking) {
} else {
// If we can't clear the decode policy, we need to make sure we still
// re-decode and checker images that were pending invalidation.
for (auto image_id : images_pending_invalidation_) {
auto it = image_async_decode_state_.find(image_id);
DCHECK(it != image_async_decode_state_.end());
DCHECK_EQ(it->second.policy, DecodePolicy::SYNC);
it->second.policy = DecodePolicy::ASYNC;
void CheckerImageTracker::DisallowCheckeringForImage(const PaintImage& image) {
std::make_pair(image.stable_id(), DecodeState()));
void CheckerImageTracker::DidFinishImageDecode(
PaintImage::Id image_id,
ImageController::ImageDecodeRequestId request_id,
ImageController::ImageDecodeResult result) {
TRACE_EVENT_ASYNC_END0("cc", "CheckerImageTracker::DeferImageDecode",
DCHECK_NE(ImageController::ImageDecodeResult::DECODE_NOT_REQUIRED, result);
DCHECK_EQ(outstanding_image_decode_.value().stable_id(), image_id);
// The async decode state may have been cleared if the tracker was cleared
// before this decode could be finished.
auto it = image_async_decode_state_.find(image_id);
if (it == image_async_decode_state_.end()) {
DCHECK_EQ(image_id_to_decode_.count(image_id), 0u);
// We might have flipped this to sync while updating the hints. That function
// would have also requested an invalidation, so we can just schedule the next
// decode here.
if (it->second.policy == DecodePolicy::SYNC) {
DCHECK(decoding_mode_map_.find(image_id) != decoding_mode_map_.end());
DCHECK_EQ(decoding_mode_map_[image_id], PaintImage::DecodingMode::kSync);
it->second.policy = DecodePolicy::SYNC;
bool CheckerImageTracker::ShouldCheckerImage(const DrawImage& draw_image,
WhichTree tree) {
const PaintImage& image = draw_image.paint_image();
PaintImage::Id image_id = image.stable_id();
TRACE_EVENT1("cc.debug", "CheckerImageTracker::ShouldCheckerImage",
"image_id", image_id);
// Checkering of all images is disabled.
if (!enable_checker_imaging_)
return false;
// If the image was invalidated on the current sync tree and the tile is
// for the active tree, continue checkering it on the active tree to ensure
// the image update is atomic for the frame.
if (invalidated_images_on_current_sync_tree_.count(image_id) != 0 &&
tree == WhichTree::ACTIVE_TREE) {
return true;
// If the image is pending invalidation, continue checkering it. All tiles
// for these images will be invalidated on the next pending tree.
if (images_pending_invalidation_.find(image_id) !=
images_pending_invalidation_.end()) {
return true;
auto decoding_mode_it = decoding_mode_map_.find(image_id);
PaintImage::DecodingMode decoding_mode_hint =
decoding_mode_it == decoding_mode_map_.end()
? PaintImage::DecodingMode::kUnspecified
: decoding_mode_it->second;
// We only checker images if the developer specifies async decoding mode.
if (decoding_mode_hint != PaintImage::DecodingMode::kAsync)
return false;
auto insert_result = image_async_decode_state_.insert(
std::pair<PaintImage::Id, DecodeState>(image_id, DecodeState()));
auto it = insert_result.first;
if (insert_result.second) {
CheckerImagingDecision decision = CheckerImagingDecision::kCanChecker;
// If the mode is sync, then don't checker this image.
// TODO(vmpstr): Figure out if we should do something different in other
// cases.
if (decoding_mode_hint == PaintImage::DecodingMode::kSync)
decision = CheckerImagingDecision::kVetoedSyncRequested;
// The following conditions must be true for an image to be checkerable:
// 1) Complete: The data for the image should have been completely loaded.
// 2) Static: Animated images/video frames can not be checkered.
// 3) Size constraints: Small images for which the decode is expected to
// be fast and large images which would breach the image cache budget and
// go through the at-raster decode path are not checkered.
// 4) Multipart images: Multipart images can be used to display mjpg video
// frames, checkering which would cause each video frame to flash and
// therefore should not be checkered.
// Note that we only need to do this check if we didn't veto above in this
// block.
if (decision == CheckerImagingDecision::kCanChecker) {
decision = GetCheckerImagingDecision(
image, draw_image.src_rect(), min_image_bytes_to_checker_,
if (decision == CheckerImagingDecision::kCanChecker && force_disabled_) {
// Get the decision for all the veto reasons first, so we can UMA the
// images that were not checkered only because checker-imaging was force
// disabled.
decision = CheckerImagingDecision::kVetoedForceDisable;
it->second.policy = decision == CheckerImagingDecision::kCanChecker
? DecodePolicy::ASYNC
: DecodePolicy::SYNC;
"Compositing.Renderer.CheckerImagingDecision", decision,
"CheckerImageTracker::CheckerImagingDecision", "image_params",
ToString(image_id, decision));
// Update the decode state from the latest image we have seen. Note that it
// is not necessary to perform this in the early out cases above since in
// each of those cases the image has already been decoded.
UpdateDecodeState(draw_image, image_id, &it->second);
return it->second.policy == DecodePolicy::ASYNC;
void CheckerImageTracker::UpdateDecodeState(const DrawImage& draw_image,
PaintImage::Id paint_image_id,
DecodeState* decode_state) {
// If the policy is not async then either we decoded this image already or
// we decided not to ever checker it.
if (decode_state->policy != DecodePolicy::ASYNC)
// If the decode is already in flight, then we will have to live with what we
// have now.
if (outstanding_image_decode_.has_value() &&
outstanding_image_decode_.value().stable_id() == paint_image_id) {
// Choose the max scale and filter quality. This keeps the memory usage to the
// minimum possible while still increasing the possibility of getting a cache
// hit.
decode_state->scale = SkSize::Make(
std::max(decode_state->scale.fWidth, draw_image.scale().fWidth),
std::max(decode_state->scale.fHeight, draw_image.scale().fHeight));
decode_state->filter_quality =
std::max(decode_state->filter_quality, draw_image.filter_quality());
decode_state->frame_index = draw_image.frame_index();
void CheckerImageTracker::ScheduleNextImageDecode() {
// We can have only one outstanding decode pending completion with the decode
// service. We'll come back here when it is completed.
if (outstanding_image_decode_.has_value())
if (image_decode_queue_.empty())
// If scheduling decodes for this priority is not allowed right now, don't
// schedule them. We will come back here when the allowed priority changes.
if (image_decode_queue_.front().type > decode_priority_allowed_)
DrawImage draw_image;
while (!image_decode_queue_.empty()) {
auto candidate = std::move(image_decode_queue_.front().paint_image);
// Once an image has been decoded, it can still be present in the decode
// queue (duplicate entries), or while an image is still being skipped on
// the active tree. Check if the image is still ASYNC to see if a decode is
// needed.
PaintImage::Id image_id = candidate.stable_id();
auto it = image_async_decode_state_.find(image_id);
DCHECK(it != image_async_decode_state_.end());
if (it->second.policy != DecodePolicy::ASYNC)
draw_image = DrawImage(
candidate, SkIRect::MakeWH(candidate.width(), candidate.height()),
// We either found an image to decode or we reached the end of the queue. If
// we couldn't find an image, we're done.
if (!outstanding_image_decode_.has_value()) {
PaintImage::Id image_id = outstanding_image_decode_.value().stable_id();
DCHECK_EQ(image_id_to_decode_.count(image_id), 0u);
TRACE_EVENT_ASYNC_BEGIN0("cc", "CheckerImageTracker::DeferImageDecode",
ImageController::ImageDecodeRequestId request_id =
draw_image, base::BindOnce(&CheckerImageTracker::DidFinishImageDecode,
weak_factory_.GetWeakPtr(), image_id));
image_id_to_decode_.emplace(image_id, std::make_unique<ScopedDecodeHolder>(
image_controller_, request_id));
void CheckerImageTracker::UpdateImageDecodingHints(
base::flat_map<PaintImage::Id, PaintImage::DecodingMode>
decoding_mode_map) {
// Merge the |decoding_mode_map| with our member map, keeping the more
// conservative values.
// TODO(vmpstr): Figure out if and how do we clear this value to ensure that
// if we no longer have any kSync images, for example, then we can loosen the
// requirement on the decoding mode for that image id.
for (auto pair : decoding_mode_map) {
PaintImage::Id id = pair.first;
PaintImage::DecodingMode decoding_mode = pair.second;
// In case we already have this image as async, it implies that we are
// currently displaying this content as checkered. We can flip the state to
// sync here and add the image to be invalidated. The invalidation should
// happen shortly after, since this function should be called in a commit.
auto state_it = image_async_decode_state_.find(id);
if (state_it != image_async_decode_state_.end()) {
auto& state = state_it->second;
if (state.policy == DecodePolicy::ASYNC &&
decoding_mode == PaintImage::DecodingMode::kSync) {
state.policy = DecodePolicy::SYNC;
// Update the decoding hints map.
auto decoding_mode_it = decoding_mode_map_.find(id);
if (decoding_mode_it == decoding_mode_map_.end()) {
decoding_mode_map_[id] = decoding_mode;
} else {
decoding_mode_it->second =
PaintImage::GetConservative(decoding_mode_it->second, decoding_mode);
} // namespace cc