blob: b86b5503f0091b87cfdfbd4c5af0a1b44a8e9c7e [file] [log] [blame]
// Copyright 2011 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/scheduler/scheduler_state_machine.h"
#include "base/format_macros.h"
#include "base/logging.h"
#include "base/strings/stringprintf.h"
#include "base/trace_event/trace_event.h"
#include "base/trace_event/trace_event_argument.h"
#include "base/values.h"
namespace cc {
SchedulerStateMachine::SchedulerStateMachine(const SchedulerSettings& settings)
: settings_(settings),
output_surface_state_(OUTPUT_SURFACE_LOST),
begin_impl_frame_state_(BEGIN_IMPL_FRAME_STATE_IDLE),
begin_main_frame_state_(BEGIN_MAIN_FRAME_STATE_IDLE),
forced_redraw_state_(FORCED_REDRAW_STATE_IDLE),
commit_count_(0),
current_frame_number_(0),
last_frame_number_animate_performed_(-1),
last_frame_number_swap_performed_(-1),
last_frame_number_swap_requested_(-1),
last_frame_number_begin_main_frame_sent_(-1),
last_frame_number_invalidate_output_surface_performed_(-1),
animate_funnel_(false),
request_swap_funnel_(false),
send_begin_main_frame_funnel_(true),
invalidate_output_surface_funnel_(false),
prepare_tiles_funnel_(0),
consecutive_checkerboard_animations_(0),
max_pending_swaps_(1),
pending_swaps_(0),
swaps_with_current_output_surface_(0),
needs_redraw_(false),
needs_animate_(false),
needs_prepare_tiles_(false),
needs_begin_main_frame_(false),
visible_(false),
can_start_(false),
can_draw_(false),
has_pending_tree_(false),
pending_tree_is_ready_for_activation_(false),
active_tree_needs_first_draw_(false),
did_create_and_initialize_first_output_surface_(false),
impl_latency_takes_priority_(false),
main_thread_missed_last_deadline_(false),
skip_next_begin_main_frame_to_reduce_latency_(false),
children_need_begin_frames_(false),
defer_commits_(false),
video_needs_begin_frames_(false),
last_commit_had_no_updates_(false),
wait_for_ready_to_draw_(false),
did_request_swap_in_last_frame_(false),
did_perform_swap_in_last_draw_(false) {}
const char* SchedulerStateMachine::OutputSurfaceStateToString(
OutputSurfaceState state) {
switch (state) {
case OUTPUT_SURFACE_ACTIVE:
return "OUTPUT_SURFACE_ACTIVE";
case OUTPUT_SURFACE_LOST:
return "OUTPUT_SURFACE_LOST";
case OUTPUT_SURFACE_CREATING:
return "OUTPUT_SURFACE_CREATING";
case OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT:
return "OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT";
case OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION:
return "OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION";
}
NOTREACHED();
return "???";
}
const char* SchedulerStateMachine::BeginImplFrameStateToString(
BeginImplFrameState state) {
switch (state) {
case BEGIN_IMPL_FRAME_STATE_IDLE:
return "BEGIN_IMPL_FRAME_STATE_IDLE";
case BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING:
return "BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING";
case BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME:
return "BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME";
case BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE:
return "BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE";
}
NOTREACHED();
return "???";
}
const char* SchedulerStateMachine::BeginImplFrameDeadlineModeToString(
BeginImplFrameDeadlineMode mode) {
switch (mode) {
case BEGIN_IMPL_FRAME_DEADLINE_MODE_NONE:
return "BEGIN_IMPL_FRAME_DEADLINE_MODE_NONE";
case BEGIN_IMPL_FRAME_DEADLINE_MODE_IMMEDIATE:
return "BEGIN_IMPL_FRAME_DEADLINE_MODE_IMMEDIATE";
case BEGIN_IMPL_FRAME_DEADLINE_MODE_REGULAR:
return "BEGIN_IMPL_FRAME_DEADLINE_MODE_REGULAR";
case BEGIN_IMPL_FRAME_DEADLINE_MODE_LATE:
return "BEGIN_IMPL_FRAME_DEADLINE_MODE_LATE";
case BEGIN_IMPL_FRAME_DEADLINE_MODE_BLOCKED_ON_READY_TO_DRAW:
return "BEGIN_IMPL_FRAME_DEADLINE_MODE_BLOCKED_ON_READY_TO_DRAW";
}
NOTREACHED();
return "???";
}
const char* SchedulerStateMachine::BeginMainFrameStateToString(
BeginMainFrameState state) {
switch (state) {
case BEGIN_MAIN_FRAME_STATE_IDLE:
return "BEGIN_MAIN_FRAME_STATE_IDLE";
case BEGIN_MAIN_FRAME_STATE_SENT:
return "BEGIN_MAIN_FRAME_STATE_SENT";
case BEGIN_MAIN_FRAME_STATE_STARTED:
return "BEGIN_MAIN_FRAME_STATE_STARTED";
case BEGIN_MAIN_FRAME_STATE_READY_TO_COMMIT:
return "BEGIN_MAIN_FRAME_STATE_READY_TO_COMMIT";
case BEGIN_MAIN_FRAME_STATE_WAITING_FOR_ACTIVATION:
return "BEGIN_MAIN_FRAME_STATE_WAITING_FOR_ACTIVATION";
case BEGIN_MAIN_FRAME_STATE_WAITING_FOR_DRAW:
return "BEGIN_MAIN_FRAME_STATE_WAITING_FOR_DRAW";
}
NOTREACHED();
return "???";
}
const char* SchedulerStateMachine::ForcedRedrawOnTimeoutStateToString(
ForcedRedrawOnTimeoutState state) {
switch (state) {
case FORCED_REDRAW_STATE_IDLE:
return "FORCED_REDRAW_STATE_IDLE";
case FORCED_REDRAW_STATE_WAITING_FOR_COMMIT:
return "FORCED_REDRAW_STATE_WAITING_FOR_COMMIT";
case FORCED_REDRAW_STATE_WAITING_FOR_ACTIVATION:
return "FORCED_REDRAW_STATE_WAITING_FOR_ACTIVATION";
case FORCED_REDRAW_STATE_WAITING_FOR_DRAW:
return "FORCED_REDRAW_STATE_WAITING_FOR_DRAW";
}
NOTREACHED();
return "???";
}
const char* SchedulerStateMachine::ActionToString(Action action) {
switch (action) {
case ACTION_NONE:
return "ACTION_NONE";
case ACTION_ANIMATE:
return "ACTION_ANIMATE";
case ACTION_SEND_BEGIN_MAIN_FRAME:
return "ACTION_SEND_BEGIN_MAIN_FRAME";
case ACTION_COMMIT:
return "ACTION_COMMIT";
case ACTION_ACTIVATE_SYNC_TREE:
return "ACTION_ACTIVATE_SYNC_TREE";
case ACTION_DRAW_AND_SWAP_IF_POSSIBLE:
return "ACTION_DRAW_AND_SWAP_IF_POSSIBLE";
case ACTION_DRAW_AND_SWAP_FORCED:
return "ACTION_DRAW_AND_SWAP_FORCED";
case ACTION_DRAW_AND_SWAP_ABORT:
return "ACTION_DRAW_AND_SWAP_ABORT";
case ACTION_BEGIN_OUTPUT_SURFACE_CREATION:
return "ACTION_BEGIN_OUTPUT_SURFACE_CREATION";
case ACTION_PREPARE_TILES:
return "ACTION_PREPARE_TILES";
case ACTION_INVALIDATE_OUTPUT_SURFACE:
return "ACTION_INVALIDATE_OUTPUT_SURFACE";
}
NOTREACHED();
return "???";
}
scoped_refptr<base::trace_event::ConvertableToTraceFormat>
SchedulerStateMachine::AsValue() const {
scoped_refptr<base::trace_event::TracedValue> state =
new base::trace_event::TracedValue();
AsValueInto(state.get());
return state;
}
void SchedulerStateMachine::AsValueInto(
base::trace_event::TracedValue* state) const {
state->BeginDictionary("major_state");
state->SetString("next_action", ActionToString(NextAction()));
state->SetString("begin_impl_frame_state",
BeginImplFrameStateToString(begin_impl_frame_state_));
state->SetString("begin_main_frame_state",
BeginMainFrameStateToString(begin_main_frame_state_));
state->SetString("output_surface_state_",
OutputSurfaceStateToString(output_surface_state_));
state->SetString("forced_redraw_state",
ForcedRedrawOnTimeoutStateToString(forced_redraw_state_));
state->EndDictionary();
state->BeginDictionary("minor_state");
state->SetInteger("commit_count", commit_count_);
state->SetInteger("current_frame_number", current_frame_number_);
state->SetInteger("last_frame_number_animate_performed",
last_frame_number_animate_performed_);
state->SetInteger("last_frame_number_swap_performed",
last_frame_number_swap_performed_);
state->SetInteger("last_frame_number_swap_requested",
last_frame_number_swap_requested_);
state->SetInteger("last_frame_number_begin_main_frame_sent",
last_frame_number_begin_main_frame_sent_);
state->SetBoolean("funnel: animate_funnel", animate_funnel_);
state->SetBoolean("funnel: request_swap_funnel", request_swap_funnel_);
state->SetBoolean("funnel: send_begin_main_frame_funnel",
send_begin_main_frame_funnel_);
state->SetInteger("funnel: prepare_tiles_funnel", prepare_tiles_funnel_);
state->SetBoolean("funnel: invalidate_output_surface_funnel",
invalidate_output_surface_funnel_);
state->SetInteger("consecutive_checkerboard_animations",
consecutive_checkerboard_animations_);
state->SetInteger("max_pending_swaps_", max_pending_swaps_);
state->SetInteger("pending_swaps_", pending_swaps_);
state->SetInteger("swaps_with_current_output_surface",
swaps_with_current_output_surface_);
state->SetBoolean("needs_redraw", needs_redraw_);
state->SetBoolean("needs_animate_", needs_animate_);
state->SetBoolean("needs_prepare_tiles", needs_prepare_tiles_);
state->SetBoolean("needs_begin_main_frame", needs_begin_main_frame_);
state->SetBoolean("visible", visible_);
state->SetBoolean("can_start", can_start_);
state->SetBoolean("can_draw", can_draw_);
state->SetBoolean("has_pending_tree", has_pending_tree_);
state->SetBoolean("pending_tree_is_ready_for_activation",
pending_tree_is_ready_for_activation_);
state->SetBoolean("active_tree_needs_first_draw",
active_tree_needs_first_draw_);
state->SetBoolean("wait_for_ready_to_draw", wait_for_ready_to_draw_);
state->SetBoolean("did_create_and_initialize_first_output_surface",
did_create_and_initialize_first_output_surface_);
state->SetBoolean("impl_latency_takes_priority",
impl_latency_takes_priority_);
state->SetBoolean("main_thread_missed_last_deadline",
main_thread_missed_last_deadline_);
state->SetBoolean("skip_next_begin_main_frame_to_reduce_latency",
skip_next_begin_main_frame_to_reduce_latency_);
state->SetBoolean("children_need_begin_frames", children_need_begin_frames_);
state->SetBoolean("video_needs_begin_frames", video_needs_begin_frames_);
state->SetBoolean("defer_commits", defer_commits_);
state->SetBoolean("last_commit_had_no_updates", last_commit_had_no_updates_);
state->SetBoolean("did_request_swap_in_last_frame",
did_request_swap_in_last_frame_);
state->SetBoolean("did_perform_swap_in_last_draw",
did_perform_swap_in_last_draw_);
state->EndDictionary();
}
bool SchedulerStateMachine::PendingDrawsShouldBeAborted() const {
// These are all the cases where we normally cannot or do not want to draw
// but, if needs_redraw_ is true and we do not draw to make forward progress,
// we might deadlock with the main thread.
// This should be a superset of PendingActivationsShouldBeForced() since
// activation of the pending tree is blocked by drawing of the active tree and
// the main thread might be blocked on activation of the most recent commit.
if (PendingActivationsShouldBeForced())
return true;
// Additional states where we should abort draws.
if (!can_draw_)
return true;
return false;
}
bool SchedulerStateMachine::PendingActivationsShouldBeForced() const {
// There is no output surface to trigger our activations.
// If we do not force activations to make forward progress, we might deadlock
// with the main thread.
if (output_surface_state_ == OUTPUT_SURFACE_LOST)
return true;
// If we're not visible, we should force activation.
// Since we set RequiresHighResToDraw when becoming visible, we ensure that we
// don't checkerboard until all visible resources are done. Furthermore, if we
// do keep the pending tree around, when becoming visible we might activate
// prematurely causing RequiresHighResToDraw flag to be reset. In all cases,
// we can simply activate on becoming invisible since we don't need to draw
// the active tree when we're in this state.
if (!visible_)
return true;
return false;
}
bool SchedulerStateMachine::ShouldBeginOutputSurfaceCreation() const {
if (!visible_)
return false;
// Don't try to initialize too early.
if (!can_start_)
return false;
// We only want to start output surface initialization after the
// previous commit is complete.
if (begin_main_frame_state_ != BEGIN_MAIN_FRAME_STATE_IDLE)
return false;
// Make sure the BeginImplFrame from any previous OutputSurfaces
// are complete before creating the new OutputSurface.
if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_IDLE)
return false;
// We want to clear the pipeline of any pending draws and activations
// before starting output surface initialization. This allows us to avoid
// weird corner cases where we abort draws or force activation while we
// are initializing the output surface.
if (active_tree_needs_first_draw_ || has_pending_tree_)
return false;
// We need to create the output surface if we don't have one and we haven't
// started creating one yet.
return output_surface_state_ == OUTPUT_SURFACE_LOST;
}
bool SchedulerStateMachine::ShouldDraw() const {
// If we need to abort draws, we should do so ASAP since the draw could
// be blocking other important actions (like output surface initialization),
// from occurring. If we are waiting for the first draw, then perform the
// aborted draw to keep things moving. If we are not waiting for the first
// draw however, we don't want to abort for no reason.
if (PendingDrawsShouldBeAborted())
return active_tree_needs_first_draw_;
// Do not draw too many times in a single frame. It's okay that we don't check
// this before checking for aborted draws because aborted draws do not request
// a swap.
if (request_swap_funnel_)
return false;
// Don't draw if we are waiting on the first commit after a surface.
if (output_surface_state_ != OUTPUT_SURFACE_ACTIVE)
return false;
// Do not queue too many swaps.
if (SwapThrottled())
return false;
// Except for the cases above, do not draw outside of the BeginImplFrame
// deadline.
if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE)
return false;
// Only handle forced redraws due to timeouts on the regular deadline.
if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW)
return true;
return needs_redraw_;
}
bool SchedulerStateMachine::ShouldActivatePendingTree() const {
// There is nothing to activate.
if (!has_pending_tree_)
return false;
// We should not activate a second tree before drawing the first one.
// Even if we need to force activation of the pending tree, we should abort
// drawing the active tree first.
if (active_tree_needs_first_draw_)
return false;
// If we want to force activation, do so ASAP.
if (PendingActivationsShouldBeForced())
return true;
// At this point, only activate if we are ready to activate.
return pending_tree_is_ready_for_activation_;
}
bool SchedulerStateMachine::ShouldAnimate() const {
// Do not animate too many times in a single frame.
if (animate_funnel_)
return false;
// Don't animate if we are waiting on the first commit after a surface.
if (output_surface_state_ != OUTPUT_SURFACE_ACTIVE)
return false;
if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING &&
begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE)
return false;
return needs_redraw_ || needs_animate_;
}
bool SchedulerStateMachine::CouldSendBeginMainFrame() const {
if (!needs_begin_main_frame_)
return false;
// We can not perform commits if we are not visible.
if (!visible_)
return false;
// Do not make a new commits when it is deferred.
if (defer_commits_)
return false;
return true;
}
bool SchedulerStateMachine::SendingBeginMainFrameMightCauseDeadlock() const {
// NPAPI is the only case where the UI thread makes synchronous calls to the
// Renderer main thread. During that synchronous call, we may not get a
// SwapAck for the UI thread, which may prevent BeginMainFrame's from
// completing if there's enough back pressure. If the BeginMainFrame can't
// make progress, the Renderer can't service the UI thread's synchronous call
// and we have deadlock.
// This returns true if there's too much backpressure to finish a commit
// if we were to initiate a BeginMainFrame.
return has_pending_tree_ && active_tree_needs_first_draw_ && SwapThrottled();
}
bool SchedulerStateMachine::ShouldSendBeginMainFrame() const {
if (!CouldSendBeginMainFrame())
return false;
// Do not send begin main frame too many times in a single frame or before
// the first BeginFrame.
if (send_begin_main_frame_funnel_)
return false;
// Only send BeginMainFrame when there isn't another commit pending already.
// Other parts of the state machine indirectly defer the BeginMainFrame
// by transitioning to WAITING commit states rather than going
// immediately to IDLE.
if (begin_main_frame_state_ != BEGIN_MAIN_FRAME_STATE_IDLE)
return false;
// Don't send BeginMainFrame early if we are prioritizing the active tree
// because of impl_latency_takes_priority_.
if (impl_latency_takes_priority_ &&
(has_pending_tree_ || active_tree_needs_first_draw_)) {
return false;
}
// We should not send BeginMainFrame while we are in the idle state since we
// might have new user input arriving soon. It's okay to send BeginMainFrame
// for the synchronous compositor because the main thread is always high
// latency in that case.
// TODO(brianderson): Allow sending BeginMainFrame while idle when the main
// thread isn't consuming user input for non-synchronous compositor.
if (!settings_.using_synchronous_renderer_compositor &&
begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_IDLE) {
return false;
}
// We need a new commit for the forced redraw. This honors the
// single commit per interval because the result will be swapped to screen.
// TODO(brianderson): Remove this or move it below the
// SendingBeginMainFrameMightCauseDeadlock check since we want to avoid
// ever returning true from this method if we might cause deadlock.
if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_COMMIT)
return true;
// We shouldn't normally accept commits if there isn't an OutputSurface.
if (!HasInitializedOutputSurface())
return false;
// Make sure the BeginMainFrame can finish eventually if we start it.
if (SendingBeginMainFrameMightCauseDeadlock())
return false;
if (!settings_.main_frame_while_swap_throttled_enabled) {
// SwapAck throttle the BeginMainFrames unless we just swapped to
// potentially improve impl-thread latency over main-thread throughput.
// TODO(brianderson): Remove this restriction to improve throughput or
// make it conditional on impl_latency_takes_priority_.
bool just_swapped_in_deadline =
begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE &&
did_perform_swap_in_last_draw_;
if (SwapThrottled() && !just_swapped_in_deadline)
return false;
}
if (skip_next_begin_main_frame_to_reduce_latency_)
return false;
return true;
}
bool SchedulerStateMachine::ShouldCommit() const {
if (begin_main_frame_state_ != BEGIN_MAIN_FRAME_STATE_READY_TO_COMMIT)
return false;
// We must not finish the commit until the pending tree is free.
if (has_pending_tree_) {
DCHECK(settings_.main_frame_before_activation_enabled);
return false;
}
// If we only have an active tree, it is incorrect to replace it
// before we've drawn it.
DCHECK_IMPLIES(settings_.commit_to_active_tree,
!active_tree_needs_first_draw_);
return true;
}
bool SchedulerStateMachine::ShouldPrepareTiles() const {
// PrepareTiles only really needs to be called immediately after commit
// and then periodically after that. Use a funnel to make sure we average
// one PrepareTiles per BeginImplFrame in the long run.
if (prepare_tiles_funnel_ > 0)
return false;
// Limiting to once per-frame is not enough, since we only want to
// prepare tiles _after_ draws.
if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE)
return false;
return needs_prepare_tiles_;
}
bool SchedulerStateMachine::ShouldInvalidateOutputSurface() const {
// Do not invalidate too many times in a frame.
if (invalidate_output_surface_funnel_)
return false;
// Only the synchronous compositor requires invalidations.
if (!settings_.using_synchronous_renderer_compositor)
return false;
// Invalidations are only performed inside a BeginFrame.
if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING)
return false;
// TODO(sunnyps): needs_prepare_tiles_ is needed here because PrepareTiles is
// called only inside the deadline / draw phase. We could remove this if we
// allowed PrepareTiles to happen in OnBeginImplFrame.
return needs_redraw_ || needs_prepare_tiles_;
}
SchedulerStateMachine::Action SchedulerStateMachine::NextAction() const {
if (ShouldActivatePendingTree())
return ACTION_ACTIVATE_SYNC_TREE;
if (ShouldCommit())
return ACTION_COMMIT;
if (ShouldAnimate())
return ACTION_ANIMATE;
if (ShouldDraw()) {
if (PendingDrawsShouldBeAborted())
return ACTION_DRAW_AND_SWAP_ABORT;
else if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW)
return ACTION_DRAW_AND_SWAP_FORCED;
else
return ACTION_DRAW_AND_SWAP_IF_POSSIBLE;
}
if (ShouldPrepareTiles())
return ACTION_PREPARE_TILES;
if (ShouldSendBeginMainFrame())
return ACTION_SEND_BEGIN_MAIN_FRAME;
if (ShouldInvalidateOutputSurface())
return ACTION_INVALIDATE_OUTPUT_SURFACE;
if (ShouldBeginOutputSurfaceCreation())
return ACTION_BEGIN_OUTPUT_SURFACE_CREATION;
return ACTION_NONE;
}
void SchedulerStateMachine::WillAnimate() {
DCHECK(!animate_funnel_);
last_frame_number_animate_performed_ = current_frame_number_;
animate_funnel_ = true;
needs_animate_ = false;
// TODO(skyostil): Instead of assuming this, require the client to tell us.
SetNeedsRedraw();
}
void SchedulerStateMachine::WillSendBeginMainFrame() {
DCHECK(!has_pending_tree_ || settings_.main_frame_before_activation_enabled);
DCHECK(visible_);
DCHECK(!send_begin_main_frame_funnel_);
begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_SENT;
needs_begin_main_frame_ = false;
send_begin_main_frame_funnel_ = true;
last_frame_number_begin_main_frame_sent_ = current_frame_number_;
}
void SchedulerStateMachine::WillCommit(bool commit_has_no_updates) {
commit_count_++;
// Animate after commit even if we've already animated.
if (!commit_has_no_updates)
animate_funnel_ = false;
if (commit_has_no_updates || settings_.main_frame_before_activation_enabled) {
begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_IDLE;
} else {
begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_WAITING_FOR_ACTIVATION;
}
// If the commit was aborted, then there is no pending tree.
has_pending_tree_ = !commit_has_no_updates;
wait_for_ready_to_draw_ =
!commit_has_no_updates && settings_.commit_to_active_tree;
// Update state related to forced draws.
if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_COMMIT) {
forced_redraw_state_ = has_pending_tree_
? FORCED_REDRAW_STATE_WAITING_FOR_ACTIVATION
: FORCED_REDRAW_STATE_WAITING_FOR_DRAW;
}
// Update the output surface state.
DCHECK_NE(output_surface_state_, OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION);
if (output_surface_state_ == OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT) {
if (has_pending_tree_) {
output_surface_state_ = OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION;
} else {
output_surface_state_ = OUTPUT_SURFACE_ACTIVE;
}
}
// Update state if there's no updates heading for the active tree, but we need
// to do a forced draw.
if (commit_has_no_updates &&
forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW) {
DCHECK(!has_pending_tree_);
needs_redraw_ = true;
active_tree_needs_first_draw_ = true;
}
// This post-commit work is common to both completed and aborted commits.
pending_tree_is_ready_for_activation_ = false;
last_commit_had_no_updates_ = commit_has_no_updates;
}
void SchedulerStateMachine::WillActivate() {
if (begin_main_frame_state_ ==
BEGIN_MAIN_FRAME_STATE_WAITING_FOR_ACTIVATION) {
begin_main_frame_state_ = settings_.commit_to_active_tree
? BEGIN_MAIN_FRAME_STATE_WAITING_FOR_DRAW
: BEGIN_MAIN_FRAME_STATE_IDLE;
}
if (output_surface_state_ == OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION)
output_surface_state_ = OUTPUT_SURFACE_ACTIVE;
if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_ACTIVATION)
forced_redraw_state_ = FORCED_REDRAW_STATE_WAITING_FOR_DRAW;
has_pending_tree_ = false;
pending_tree_is_ready_for_activation_ = false;
active_tree_needs_first_draw_ = true;
needs_redraw_ = true;
}
void SchedulerStateMachine::WillDraw(bool did_request_swap) {
if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW)
forced_redraw_state_ = FORCED_REDRAW_STATE_IDLE;
if (begin_main_frame_state_ == BEGIN_MAIN_FRAME_STATE_WAITING_FOR_DRAW)
begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_IDLE;
needs_redraw_ = false;
active_tree_needs_first_draw_ = false;
if (did_request_swap) {
DCHECK(!request_swap_funnel_);
request_swap_funnel_ = true;
did_request_swap_in_last_frame_ = true;
last_frame_number_swap_requested_ = current_frame_number_;
}
}
void SchedulerStateMachine::WillPrepareTiles() {
needs_prepare_tiles_ = false;
}
void SchedulerStateMachine::WillBeginOutputSurfaceCreation() {
DCHECK_EQ(output_surface_state_, OUTPUT_SURFACE_LOST);
output_surface_state_ = OUTPUT_SURFACE_CREATING;
// The following DCHECKs make sure we are in the proper quiescent state.
// The pipeline should be flushed entirely before we start output
// surface creation to avoid complicated corner cases.
DCHECK_EQ(begin_main_frame_state_, BEGIN_MAIN_FRAME_STATE_IDLE);
DCHECK(!has_pending_tree_);
DCHECK(!active_tree_needs_first_draw_);
}
void SchedulerStateMachine::WillInvalidateOutputSurface() {
DCHECK(!invalidate_output_surface_funnel_);
invalidate_output_surface_funnel_ = true;
last_frame_number_invalidate_output_surface_performed_ =
current_frame_number_;
// The synchronous compositor makes no guarantees about a draw coming in after
// an invalidate so clear any flags that would cause the compositor's pipeline
// to stall.
active_tree_needs_first_draw_ = false; // blocks commit if true
}
void SchedulerStateMachine::SetSkipNextBeginMainFrameToReduceLatency() {
TRACE_EVENT_INSTANT0("cc",
"Scheduler: SkipNextBeginMainFrameToReduceLatency",
TRACE_EVENT_SCOPE_THREAD);
skip_next_begin_main_frame_to_reduce_latency_ = true;
}
bool SchedulerStateMachine::BeginFrameRequiredForChildren() const {
return children_need_begin_frames_;
}
bool SchedulerStateMachine::BeginFrameNeededForVideo() const {
return video_needs_begin_frames_;
}
bool SchedulerStateMachine::BeginFrameNeeded() const {
// We can't handle BeginFrames when output surface isn't initialized.
// TODO(brianderson): Support output surface creation inside a BeginFrame.
if (!HasInitializedOutputSurface())
return false;
// If we are not visible, we don't need BeginFrame messages.
if (!visible_)
return false;
return (BeginFrameRequiredForAction() || BeginFrameRequiredForChildren() ||
BeginFrameNeededForVideo() || ProactiveBeginFrameWanted());
}
void SchedulerStateMachine::SetChildrenNeedBeginFrames(
bool children_need_begin_frames) {
children_need_begin_frames_ = children_need_begin_frames;
}
void SchedulerStateMachine::SetVideoNeedsBeginFrames(
bool video_needs_begin_frames) {
video_needs_begin_frames_ = video_needs_begin_frames;
}
void SchedulerStateMachine::SetDeferCommits(bool defer_commits) {
defer_commits_ = defer_commits;
}
// These are the cases where we require a BeginFrame message to make progress
// on requested actions.
bool SchedulerStateMachine::BeginFrameRequiredForAction() const {
// The forced draw respects our normal draw scheduling, so we need to
// request a BeginImplFrame for it.
if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW)
return true;
return needs_animate_ || needs_redraw_ ||
(needs_begin_main_frame_ && !defer_commits_);
}
// These are cases where we are very likely want a BeginFrame message in the
// near future. Proactively requesting the BeginImplFrame helps hide the round
// trip latency of the SetNeedsBeginFrame request that has to go to the
// Browser.
// This includes things like drawing soon, but might not actually have a new
// frame to draw when we receive the next BeginImplFrame.
bool SchedulerStateMachine::ProactiveBeginFrameWanted() const {
// Do not be proactive when invisible.
if (!visible_)
return false;
// We should proactively request a BeginImplFrame if a commit is pending
// because we will want to draw if the commit completes quickly. Do not
// request frames when commits are disabled, because the frame requests will
// not provide the needed commit (and will wake up the process when it could
// stay idle).
if ((begin_main_frame_state_ != BEGIN_MAIN_FRAME_STATE_IDLE) &&
!defer_commits_)
return true;
// If the pending tree activates quickly, we'll want a BeginImplFrame soon
// to draw the new active tree.
if (has_pending_tree_)
return true;
// Changing priorities may allow us to activate (given the new priorities),
// which may result in a new frame.
if (needs_prepare_tiles_)
return true;
// If we just sent a swap request, it's likely that we are going to produce
// another frame soon. This helps avoid negative glitches in our
// SetNeedsBeginFrame requests, which may propagate to the BeginImplFrame
// provider and get sampled at an inopportune time, delaying the next
// BeginImplFrame.
if (did_request_swap_in_last_frame_)
return true;
// If the last commit was aborted because of early out (no updates), we should
// still want a begin frame in case there is a commit coming again.
if (last_commit_had_no_updates_)
return true;
return false;
}
void SchedulerStateMachine::OnBeginImplFrame() {
begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING;
current_frame_number_++;
last_commit_had_no_updates_ = false;
did_request_swap_in_last_frame_ = false;
// Clear funnels for any actions we perform during the frame.
animate_funnel_ = false;
send_begin_main_frame_funnel_ = false;
invalidate_output_surface_funnel_ = false;
// "Drain" the PrepareTiles funnel.
if (prepare_tiles_funnel_ > 0)
prepare_tiles_funnel_--;
}
void SchedulerStateMachine::OnBeginImplFrameDeadlinePending() {
begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME;
}
void SchedulerStateMachine::OnBeginImplFrameDeadline() {
begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE;
did_perform_swap_in_last_draw_ = false;
// Clear funnels for any actions we perform during the deadline.
request_swap_funnel_ = false;
// Allow one PrepareTiles per draw for synchronous compositor.
if (settings_.using_synchronous_renderer_compositor) {
if (prepare_tiles_funnel_ > 0)
prepare_tiles_funnel_--;
}
}
void SchedulerStateMachine::OnBeginImplFrameIdle() {
begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_IDLE;
skip_next_begin_main_frame_to_reduce_latency_ = false;
// If a new or undrawn active tree is pending after the deadline,
// then the main thread is in a high latency mode.
main_thread_missed_last_deadline_ =
CommitPending() || has_pending_tree_ || active_tree_needs_first_draw_;
// If we're entering a state where we won't get BeginFrames set all the
// funnels so that we don't perform any actions that we shouldn't.
if (!BeginFrameNeeded())
send_begin_main_frame_funnel_ = true;
}
SchedulerStateMachine::BeginImplFrameDeadlineMode
SchedulerStateMachine::CurrentBeginImplFrameDeadlineMode() const {
if (settings_.using_synchronous_renderer_compositor) {
// No deadline for synchronous compositor.
return BEGIN_IMPL_FRAME_DEADLINE_MODE_NONE;
} else if (ShouldTriggerBeginImplFrameDeadlineImmediately()) {
return BEGIN_IMPL_FRAME_DEADLINE_MODE_IMMEDIATE;
} else if (wait_for_ready_to_draw_) {
// When we are waiting for ready to draw signal, we do not wait to post a
// deadline yet.
return BEGIN_IMPL_FRAME_DEADLINE_MODE_BLOCKED_ON_READY_TO_DRAW;
} else if (needs_redraw_ && !SwapThrottled()) {
// We have an animation or fast input path on the impl thread that wants
// to draw, so don't wait too long for a new active tree.
// If we are swap throttled we should wait until we are unblocked.
return BEGIN_IMPL_FRAME_DEADLINE_MODE_REGULAR;
} else {
// The impl thread doesn't have anything it wants to draw and we are just
// waiting for a new active tree or we are swap throttled. In short we are
// blocked.
return BEGIN_IMPL_FRAME_DEADLINE_MODE_LATE;
}
}
bool SchedulerStateMachine::ShouldTriggerBeginImplFrameDeadlineImmediately()
const {
// If we just forced activation, we should end the deadline right now.
if (PendingActivationsShouldBeForced() && !has_pending_tree_)
return true;
// Do not trigger deadline immediately if we're waiting for READY_TO_DRAW
// unless it's one of the forced cases.
if (wait_for_ready_to_draw_)
return false;
// SwapAck throttle the deadline since we wont draw and swap anyway.
if (SwapThrottled())
return false;
if (active_tree_needs_first_draw_)
return true;
if (!needs_redraw_)
return false;
// This is used to prioritize impl-thread draws when the main thread isn't
// producing anything, e.g., after an aborted commit. We also check that we
// don't have a pending tree -- otherwise we should give it a chance to
// activate.
// TODO(skyostil): Revisit this when we have more accurate deadline estimates.
if (begin_main_frame_state_ == BEGIN_MAIN_FRAME_STATE_IDLE &&
!has_pending_tree_)
return true;
// Prioritize impl-thread draws in impl_latency_takes_priority_ mode.
if (impl_latency_takes_priority_)
return true;
return false;
}
bool SchedulerStateMachine::main_thread_missed_last_deadline() const {
return main_thread_missed_last_deadline_;
}
bool SchedulerStateMachine::SwapThrottled() const {
return pending_swaps_ >= max_pending_swaps_;
}
void SchedulerStateMachine::SetVisible(bool visible) {
if (visible_ == visible)
return;
visible_ = visible;
if (visible)
main_thread_missed_last_deadline_ = false;
// TODO(sunnyps): Change the funnel to a bool to avoid hacks like this.
prepare_tiles_funnel_ = 0;
wait_for_ready_to_draw_ = false;
}
void SchedulerStateMachine::SetCanDraw(bool can_draw) { can_draw_ = can_draw; }
void SchedulerStateMachine::SetNeedsRedraw() { needs_redraw_ = true; }
void SchedulerStateMachine::SetNeedsAnimate() {
needs_animate_ = true;
}
bool SchedulerStateMachine::OnlyImplSideUpdatesExpected() const {
bool has_impl_updates = needs_redraw_ || needs_animate_;
bool main_updates_expected =
needs_begin_main_frame_ ||
begin_main_frame_state_ != BEGIN_MAIN_FRAME_STATE_IDLE ||
has_pending_tree_;
return has_impl_updates && !main_updates_expected;
}
void SchedulerStateMachine::SetNeedsPrepareTiles() {
if (!needs_prepare_tiles_) {
TRACE_EVENT0("cc", "SchedulerStateMachine::SetNeedsPrepareTiles");
needs_prepare_tiles_ = true;
}
}
void SchedulerStateMachine::SetMaxSwapsPending(int max) {
max_pending_swaps_ = max;
}
void SchedulerStateMachine::DidSwapBuffers() {
pending_swaps_++;
swaps_with_current_output_surface_++;
DCHECK_LE(pending_swaps_, max_pending_swaps_);
did_perform_swap_in_last_draw_ = true;
last_frame_number_swap_performed_ = current_frame_number_;
}
void SchedulerStateMachine::DidSwapBuffersComplete() {
pending_swaps_--;
}
void SchedulerStateMachine::SetImplLatencyTakesPriority(
bool impl_latency_takes_priority) {
impl_latency_takes_priority_ = impl_latency_takes_priority;
}
void SchedulerStateMachine::DidDrawIfPossibleCompleted(DrawResult result) {
switch (result) {
case INVALID_RESULT:
NOTREACHED() << "Uninitialized DrawResult.";
break;
case DRAW_ABORTED_CANT_DRAW:
case DRAW_ABORTED_CONTEXT_LOST:
NOTREACHED() << "Invalid return value from DrawAndSwapIfPossible:"
<< result;
break;
case DRAW_SUCCESS:
consecutive_checkerboard_animations_ = 0;
forced_redraw_state_ = FORCED_REDRAW_STATE_IDLE;
break;
case DRAW_ABORTED_CHECKERBOARD_ANIMATIONS:
needs_redraw_ = true;
// If we're already in the middle of a redraw, we don't need to
// restart it.
if (forced_redraw_state_ != FORCED_REDRAW_STATE_IDLE)
return;
needs_begin_main_frame_ = true;
consecutive_checkerboard_animations_++;
if (settings_.timeout_and_draw_when_animation_checkerboards &&
consecutive_checkerboard_animations_ >=
settings_.maximum_number_of_failed_draws_before_draw_is_forced) {
consecutive_checkerboard_animations_ = 0;
// We need to force a draw, but it doesn't make sense to do this until
// we've committed and have new textures.
forced_redraw_state_ = FORCED_REDRAW_STATE_WAITING_FOR_COMMIT;
}
break;
case DRAW_ABORTED_MISSING_HIGH_RES_CONTENT:
// It's not clear whether this missing content is because of missing
// pictures (which requires a commit) or because of memory pressure
// removing textures (which might not). To be safe, request a commit
// anyway.
needs_begin_main_frame_ = true;
break;
}
}
void SchedulerStateMachine::SetNeedsBeginMainFrame() {
needs_begin_main_frame_ = true;
}
void SchedulerStateMachine::NotifyReadyToCommit() {
DCHECK(begin_main_frame_state_ == BEGIN_MAIN_FRAME_STATE_STARTED)
<< AsValue()->ToString();
begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_READY_TO_COMMIT;
// In commit_to_active_tree mode, commit should happen right after
// BeginFrame, meaning when this function is called, next action should be
// commit.
if (settings_.commit_to_active_tree)
DCHECK(ShouldCommit());
}
void SchedulerStateMachine::BeginMainFrameAborted(CommitEarlyOutReason reason) {
DCHECK_EQ(begin_main_frame_state_, BEGIN_MAIN_FRAME_STATE_SENT);
switch (reason) {
case CommitEarlyOutReason::ABORTED_OUTPUT_SURFACE_LOST:
case CommitEarlyOutReason::ABORTED_NOT_VISIBLE:
case CommitEarlyOutReason::ABORTED_DEFERRED_COMMIT:
begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_IDLE;
SetNeedsBeginMainFrame();
return;
case CommitEarlyOutReason::FINISHED_NO_UPDATES:
bool commit_has_no_updates = true;
WillCommit(commit_has_no_updates);
return;
}
}
void SchedulerStateMachine::DidPrepareTiles() {
needs_prepare_tiles_ = false;
// "Fill" the PrepareTiles funnel.
prepare_tiles_funnel_++;
}
void SchedulerStateMachine::DidLoseOutputSurface() {
if (output_surface_state_ == OUTPUT_SURFACE_LOST ||
output_surface_state_ == OUTPUT_SURFACE_CREATING)
return;
output_surface_state_ = OUTPUT_SURFACE_LOST;
needs_redraw_ = false;
wait_for_ready_to_draw_ = false;
}
void SchedulerStateMachine::NotifyReadyToActivate() {
if (has_pending_tree_)
pending_tree_is_ready_for_activation_ = true;
}
void SchedulerStateMachine::NotifyReadyToDraw() {
wait_for_ready_to_draw_ = false;
}
void SchedulerStateMachine::DidCreateAndInitializeOutputSurface() {
DCHECK_EQ(output_surface_state_, OUTPUT_SURFACE_CREATING);
output_surface_state_ = OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT;
if (did_create_and_initialize_first_output_surface_) {
// TODO(boliu): See if we can remove this when impl-side painting is always
// on. Does anything on the main thread need to update after recreate?
needs_begin_main_frame_ = true;
}
did_create_and_initialize_first_output_surface_ = true;
pending_swaps_ = 0;
swaps_with_current_output_surface_ = 0;
main_thread_missed_last_deadline_ = false;
}
void SchedulerStateMachine::NotifyBeginMainFrameStarted() {
DCHECK_EQ(begin_main_frame_state_, BEGIN_MAIN_FRAME_STATE_SENT);
begin_main_frame_state_ = BEGIN_MAIN_FRAME_STATE_STARTED;
}
bool SchedulerStateMachine::HasInitializedOutputSurface() const {
switch (output_surface_state_) {
case OUTPUT_SURFACE_LOST:
case OUTPUT_SURFACE_CREATING:
return false;
case OUTPUT_SURFACE_ACTIVE:
case OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT:
case OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION:
return true;
}
NOTREACHED();
return false;
}
} // namespace cc