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[Impeller] Add keep alive for 4 frames in render target cache. (flutter/engine#57020)

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Improve cache usage by keeping textures alive for 4 frames after the last usage. This improves cache usage in scenarios such as repeatidly dragging the android overscroll functionality.

THis isn't expected to have a negative impact on memory, because a texture cannot be _immediately_ deleted anyway.
This commit is contained in:
Jonah Williams 2024-12-06 13:43:56 -08:00 committed by GitHub
parent 13c0f5ad58
commit d58cd98b8c
3 changed files with 68 additions and 23 deletions
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41
engine/src/flutter/impeller/entity/render_target_cache.cc
View File

@ -8,8 +8,10 @@
namespace impeller {
RenderTargetCache::RenderTargetCache(std::shared_ptr<Allocator> allocator)
: RenderTargetAllocator(std::move(allocator)) {}
RenderTargetCache::RenderTargetCache(std::shared_ptr<Allocator> allocator,
uint32_t keep_alive_frame_count)
: RenderTargetAllocator(std::move(allocator)),
keep_alive_frame_count_(keep_alive_frame_count) {}
void RenderTargetCache::Start() {
for (auto& td : render_target_data_) {
@ -20,9 +22,12 @@ void RenderTargetCache::Start() {
void RenderTargetCache::End() {
std::vector<RenderTargetData> retain;
for (const auto& td : render_target_data_) {
for (RenderTargetData& td : render_target_data_) {
if (td.used_this_frame) {
retain.push_back(td);
} else if (td.keep_alive_frame_count > 0) {
td.keep_alive_frame_count--;
retain.push_back(td);
}
}
render_target_data_.swap(retain);
@ -49,10 +54,11 @@ RenderTarget RenderTargetCache::CreateOffscreen(
.has_msaa = false,
.has_depth_stencil = stencil_attachment_config.has_value(),
};
for (auto& render_target_data : render_target_data_) {
const auto other_config = render_target_data.config;
for (RenderTargetData& render_target_data : render_target_data_) {
const RenderTargetConfig other_config = render_target_data.config;
if (!render_target_data.used_this_frame && other_config == config) {
render_target_data.used_this_frame = true;
render_target_data.keep_alive_frame_count = keep_alive_frame_count_;
ColorAttachment color0 =
render_target_data.render_target.GetColorAttachment(0);
std::optional<DepthAttachment> depth =
@ -69,10 +75,12 @@ RenderTarget RenderTargetCache::CreateOffscreen(
if (!created_target.IsValid()) {
return created_target;
}
render_target_data_.push_back(
RenderTargetData{.used_this_frame = true,
.config = config,
.render_target = created_target});
render_target_data_.push_back(RenderTargetData{
.used_this_frame = true, //
.keep_alive_frame_count = keep_alive_frame_count_, //
.config = config, //
.render_target = created_target //
});
return created_target;
}
@ -99,10 +107,11 @@ RenderTarget RenderTargetCache::CreateOffscreenMSAA(
.has_msaa = true,
.has_depth_stencil = stencil_attachment_config.has_value(),
};
for (auto& render_target_data : render_target_data_) {
const auto other_config = render_target_data.config;
for (RenderTargetData& render_target_data : render_target_data_) {
const RenderTargetConfig other_config = render_target_data.config;
if (!render_target_data.used_this_frame && other_config == config) {
render_target_data.used_this_frame = true;
render_target_data.keep_alive_frame_count = keep_alive_frame_count_;
ColorAttachment color0 =
render_target_data.render_target.GetColorAttachment(0);
std::optional<DepthAttachment> depth =
@ -120,10 +129,12 @@ RenderTarget RenderTargetCache::CreateOffscreenMSAA(
if (!created_target.IsValid()) {
return created_target;
}
render_target_data_.push_back(
RenderTargetData{.used_this_frame = true,
.config = config,
.render_target = created_target});
render_target_data_.push_back(RenderTargetData{
.used_this_frame = true, //
.keep_alive_frame_count = keep_alive_frame_count_, //
.config = config, //
.render_target = created_target //
});
return created_target;
}

5
engine/src/flutter/impeller/entity/render_target_cache.h
View File

@ -16,7 +16,8 @@ namespace impeller {
/// Any textures unused after a frame are immediately discarded.
class RenderTargetCache : public RenderTargetAllocator {
public:
explicit RenderTargetCache(std::shared_ptr<Allocator> allocator);
explicit RenderTargetCache(std::shared_ptr<Allocator> allocator,
uint32_t keep_alive_frame_count = 4);
~RenderTargetCache() = default;
@ -59,11 +60,13 @@ class RenderTargetCache : public RenderTargetAllocator {
private:
struct RenderTargetData {
bool used_this_frame;
uint32_t keep_alive_frame_count;
RenderTargetConfig config;
RenderTarget render_target;
};
std::vector<RenderTargetData> render_target_data_;
uint32_t keep_alive_frame_count_;
RenderTargetCache(const RenderTargetCache&) = delete;

45
engine/src/flutter/impeller/entity/render_target_cache_unittests.cc
View File

@ -50,8 +50,8 @@ class TestAllocator : public Allocator {
};
TEST_P(RenderTargetCacheTest, CachesUsedTexturesAcrossFrames) {
auto render_target_cache =
RenderTargetCache(GetContext()->GetResourceAllocator());
auto render_target_cache = RenderTargetCache(
GetContext()->GetResourceAllocator(), /*keep_alive_frame_count=*/0);
render_target_cache.Start();
// Create two render targets of the same exact size/shape. Both should be
@ -73,10 +73,41 @@ TEST_P(RenderTargetCacheTest, CachesUsedTexturesAcrossFrames) {
EXPECT_EQ(render_target_cache.CachedTextureCount(), 1u);
}
TEST_P(RenderTargetCacheTest, CachesUsedTexturesAcrossFramesWithKeepAlive) {
auto render_target_cache = RenderTargetCache(
GetContext()->GetResourceAllocator(), /*keep_alive_frame_count=*/3);
render_target_cache.Start();
// Create two render targets of the same exact size/shape. Both should be
// marked as used this frame, so the cached data set will contain two.
render_target_cache.CreateOffscreen(*GetContext(), {100, 100}, 1);
render_target_cache.CreateOffscreen(*GetContext(), {100, 100}, 1);
EXPECT_EQ(render_target_cache.CachedTextureCount(), 2u);
render_target_cache.End();
render_target_cache.Start();
// The unused texture is kept alive until the keep alive countdown
// reaches 0.
EXPECT_EQ(render_target_cache.CachedTextureCount(), 2u);
for (auto i = 0; i < 3; i++) {
render_target_cache.Start();
render_target_cache.End();
EXPECT_EQ(render_target_cache.CachedTextureCount(), 2u);
}
// After the countdown has elapsed the texture is removed.
render_target_cache.Start();
render_target_cache.End();
EXPECT_EQ(render_target_cache.CachedTextureCount(), 0u);
}
TEST_P(RenderTargetCacheTest, DoesNotPersistFailedAllocations) {
ScopedValidationDisable disable;
auto allocator = std::make_shared<TestAllocator>();
auto render_target_cache = RenderTargetCache(allocator);
auto render_target_cache =
RenderTargetCache(allocator, /*keep_alive_frame_count=*/0);
render_target_cache.Start();
allocator->should_fail = true;
@ -89,8 +120,8 @@ TEST_P(RenderTargetCacheTest, DoesNotPersistFailedAllocations) {
}
TEST_P(RenderTargetCacheTest, CachedTextureGetsNewAttachmentConfig) {
auto render_target_cache =
RenderTargetCache(GetContext()->GetResourceAllocator());
auto render_target_cache = RenderTargetCache(
GetContext()->GetResourceAllocator(), /*keep_alive_frame_count=*/0);
render_target_cache.Start();
RenderTarget::AttachmentConfig color_attachment_config =
@ -114,8 +145,8 @@ TEST_P(RenderTargetCacheTest, CachedTextureGetsNewAttachmentConfig) {
}
TEST_P(RenderTargetCacheTest, CreateWithEmptySize) {
auto render_target_cache =
RenderTargetCache(GetContext()->GetResourceAllocator());
auto render_target_cache = RenderTargetCache(
GetContext()->GetResourceAllocator(), /*keep_alive_frame_count=*/0);
render_target_cache.Start();
RenderTarget empty_target =