// 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/debug/trace_event.h" #include "base/format_macros.h" #include "base/logging.h" #include "base/strings/stringprintf.h" #include "base/values.h" #include "ui/gfx/frame_time.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), commit_state_(COMMIT_STATE_IDLE), texture_state_(LAYER_TEXTURE_STATE_UNLOCKED), forced_redraw_state_(FORCED_REDRAW_STATE_IDLE), readback_state_(READBACK_STATE_IDLE), commit_count_(0), current_frame_number_(0), last_frame_number_swap_performed_(-1), last_frame_number_begin_main_frame_sent_(-1), last_frame_number_update_visible_tiles_was_called_(-1), last_frame_number_manage_tiles_called_(-1), consecutive_failed_draws_(0), needs_redraw_(false), needs_manage_tiles_(false), swap_used_incomplete_tile_(false), needs_commit_(false), main_thread_needs_layer_textures_(false), inside_poll_for_anticipated_draw_triggers_(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), draw_if_possible_failed_(false), did_create_and_initialize_first_output_surface_(false), smoothness_takes_priority_(false), skip_begin_main_frame_to_reduce_latency_(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::CommitStateToString(CommitState state) { switch (state) { case COMMIT_STATE_IDLE: return "COMMIT_STATE_IDLE"; case COMMIT_STATE_FRAME_IN_PROGRESS: return "COMMIT_STATE_FRAME_IN_PROGRESS"; case COMMIT_STATE_READY_TO_COMMIT: return "COMMIT_STATE_READY_TO_COMMIT"; case COMMIT_STATE_WAITING_FOR_FIRST_DRAW: return "COMMIT_STATE_WAITING_FOR_FIRST_DRAW"; } NOTREACHED(); return "???"; } const char* SchedulerStateMachine::TextureStateToString(TextureState state) { switch (state) { case LAYER_TEXTURE_STATE_UNLOCKED: return "LAYER_TEXTURE_STATE_UNLOCKED"; case LAYER_TEXTURE_STATE_ACQUIRED_BY_MAIN_THREAD: return "LAYER_TEXTURE_STATE_ACQUIRED_BY_MAIN_THREAD"; case LAYER_TEXTURE_STATE_ACQUIRED_BY_IMPL_THREAD: return "LAYER_TEXTURE_STATE_ACQUIRED_BY_IMPL_THREAD"; } NOTREACHED(); return "???"; } const char* SchedulerStateMachine::SynchronousReadbackStateToString( SynchronousReadbackState state) { switch (state) { case READBACK_STATE_IDLE: return "READBACK_STATE_IDLE"; case READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME: return "READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME"; case READBACK_STATE_WAITING_FOR_COMMIT: return "READBACK_STATE_WAITING_FOR_COMMIT"; case READBACK_STATE_WAITING_FOR_ACTIVATION: return "READBACK_STATE_WAITING_FOR_ACTIVATION"; case READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK: return "READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK"; case READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT: return "READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT"; case READBACK_STATE_WAITING_FOR_REPLACEMENT_ACTIVATION: return "READBACK_STATE_WAITING_FOR_REPLACEMENT_ACTIVATION"; } 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_SEND_BEGIN_MAIN_FRAME: return "ACTION_SEND_BEGIN_MAIN_FRAME"; case ACTION_COMMIT: return "ACTION_COMMIT"; case ACTION_UPDATE_VISIBLE_TILES: return "ACTION_UPDATE_VISIBLE_TILES"; case ACTION_ACTIVATE_PENDING_TREE: return "ACTION_ACTIVATE_PENDING_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_DRAW_AND_READBACK: return "ACTION_DRAW_AND_READBACK"; case ACTION_BEGIN_OUTPUT_SURFACE_CREATION: return "ACTION_BEGIN_OUTPUT_SURFACE_CREATION"; case ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD: return "ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD"; case ACTION_MANAGE_TILES: return "ACTION_MANAGE_TILES"; } NOTREACHED(); return "???"; } scoped_ptr SchedulerStateMachine::AsValue() const { scoped_ptr state(new base::DictionaryValue); scoped_ptr major_state(new base::DictionaryValue); major_state->SetString("next_action", ActionToString(NextAction())); major_state->SetString("begin_impl_frame_state", BeginImplFrameStateToString(begin_impl_frame_state_)); major_state->SetString("commit_state", CommitStateToString(commit_state_)); major_state->SetString("texture_state_", TextureStateToString(texture_state_)); major_state->SetString("output_surface_state_", OutputSurfaceStateToString(output_surface_state_)); major_state->SetString( "forced_redraw_state", ForcedRedrawOnTimeoutStateToString(forced_redraw_state_)); major_state->SetString("readback_state", SynchronousReadbackStateToString(readback_state_)); state->Set("major_state", major_state.release()); scoped_ptr timestamps_state(new base::DictionaryValue); base::TimeTicks now = gfx::FrameTime::Now(); timestamps_state->SetDouble( "0_interval", last_begin_impl_frame_args_.interval.InMicroseconds() / 1000.0L); timestamps_state->SetDouble( "1_now_to_deadline", (last_begin_impl_frame_args_.deadline - now).InMicroseconds() / 1000.0L); timestamps_state->SetDouble( "2_frame_time_to_now", (now - last_begin_impl_frame_args_.frame_time).InMicroseconds() / 1000.0L); timestamps_state->SetDouble( "3_frame_time_to_deadline", (last_begin_impl_frame_args_.deadline - last_begin_impl_frame_args_.frame_time).InMicroseconds() / 1000.0L); timestamps_state->SetDouble( "4_now", (now - base::TimeTicks()).InMicroseconds() / 1000.0L); timestamps_state->SetDouble( "5_frame_time", (last_begin_impl_frame_args_.frame_time - base::TimeTicks()) .InMicroseconds() / 1000.0L); timestamps_state->SetDouble( "6_deadline", (last_begin_impl_frame_args_.deadline - base::TimeTicks()) .InMicroseconds() / 1000.0L); state->Set("major_timestamps_in_ms", timestamps_state.release()); scoped_ptr minor_state(new base::DictionaryValue); minor_state->SetInteger("commit_count", commit_count_); minor_state->SetInteger("current_frame_number", current_frame_number_); minor_state->SetInteger("last_frame_number_swap_performed", last_frame_number_swap_performed_); minor_state->SetInteger( "last_frame_number_begin_main_frame_sent", last_frame_number_begin_main_frame_sent_); minor_state->SetInteger( "last_frame_number_update_visible_tiles_was_called", last_frame_number_update_visible_tiles_was_called_); minor_state->SetInteger("consecutive_failed_draws", consecutive_failed_draws_); minor_state->SetBoolean("needs_redraw", needs_redraw_); minor_state->SetBoolean("needs_manage_tiles", needs_manage_tiles_); minor_state->SetBoolean("swap_used_incomplete_tile", swap_used_incomplete_tile_); minor_state->SetBoolean("needs_commit", needs_commit_); minor_state->SetBoolean("main_thread_needs_layer_textures", main_thread_needs_layer_textures_); minor_state->SetBoolean("visible", visible_); minor_state->SetBoolean("can_start", can_start_); minor_state->SetBoolean("can_draw", can_draw_); minor_state->SetBoolean("has_pending_tree", has_pending_tree_); minor_state->SetBoolean("pending_tree_is_ready_for_activation", pending_tree_is_ready_for_activation_); minor_state->SetBoolean("active_tree_needs_first_draw", active_tree_needs_first_draw_); minor_state->SetBoolean("draw_if_possible_failed", draw_if_possible_failed_); minor_state->SetBoolean("did_create_and_initialize_first_output_surface", did_create_and_initialize_first_output_surface_); minor_state->SetBoolean("smoothness_takes_priority", smoothness_takes_priority_); minor_state->SetBoolean("main_thread_is_in_high_latency_mode", MainThreadIsInHighLatencyMode()); minor_state->SetBoolean("skip_begin_main_frame_to_reduce_latency", skip_begin_main_frame_to_reduce_latency_); state->Set("minor_state", minor_state.release()); return state.PassAs(); } bool SchedulerStateMachine::HasSentBeginMainFrameThisFrame() const { return current_frame_number_ == last_frame_number_begin_main_frame_sent_; } bool SchedulerStateMachine::HasUpdatedVisibleTilesThisFrame() const { return current_frame_number_ == last_frame_number_update_visible_tiles_was_called_; } bool SchedulerStateMachine::HasSwappedThisFrame() const { return current_frame_number_ == last_frame_number_swap_performed_; } 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. // Note: We don't force activation in these cases because doing so would // result in checkerboarding on resize, becoming visible, etc. if (!can_draw_) return true; if (!visible_) return true; return false; } bool SchedulerStateMachine::PendingActivationsShouldBeForced() const { // These are all the cases where, if we do not force activations to make // forward progress, we might deadlock with the main thread. // The impl thread cannot lock layer textures unless the pending // tree can be activated to unblock the commit. if (texture_state_ == LAYER_TEXTURE_STATE_ACQUIRED_BY_MAIN_THREAD) return true; // There is no output surface to trigger our activations. if (output_surface_state_ == OUTPUT_SURFACE_LOST) return true; return false; } bool SchedulerStateMachine::ShouldBeginOutputSurfaceCreation() const { // 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 (commit_state_ != COMMIT_STATE_IDLE) return false; // We want to clear the pipline 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 and can potentially have a pending // readback. 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 { // After a readback, make sure not to draw again until we've replaced the // readback commit with a real one. if (readback_state_ == READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT || readback_state_ == READBACK_STATE_WAITING_FOR_REPLACEMENT_ACTIVATION) return false; // Draw immediately for readbacks to unblock the main thread quickly. if (readback_state_ == READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK) { DCHECK_EQ(commit_state_, COMMIT_STATE_WAITING_FOR_FIRST_DRAW); return true; } // 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 occuring. If we are waiting for the first draw, then perfom 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_; // After this line, we only want to swap once per frame. if (HasSwappedThisFrame()) 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) { DCHECK_EQ(commit_state_, COMMIT_STATE_WAITING_FOR_FIRST_DRAW); return true; } return needs_redraw_; } bool SchedulerStateMachine::ShouldAcquireLayerTexturesForMainThread() const { if (!main_thread_needs_layer_textures_) return false; if (texture_state_ == LAYER_TEXTURE_STATE_UNLOCKED) return true; DCHECK_EQ(texture_state_, LAYER_TEXTURE_STATE_ACQUIRED_BY_IMPL_THREAD); return false; } 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::ShouldUpdateVisibleTiles() const { if (!settings_.impl_side_painting) return false; if (HasUpdatedVisibleTilesThisFrame()) return false; // There's no reason to check for tiles if we don't have an output surface. if (!HasInitializedOutputSurface()) return false; // We should not check for visible tiles until we've entered the deadline so // we check as late as possible and give the tiles more time to initialize. if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE) return false; // If the last swap drew with checkerboard or missing tiles, we should // poll for any new visible tiles so we can be notified to draw again // when there are. if (swap_used_incomplete_tile_) return true; return false; } bool SchedulerStateMachine::ShouldSendBeginMainFrame() const { if (!needs_commit_) return false; // Only send BeginMainFrame when there isn't another commit pending already. if (commit_state_ != COMMIT_STATE_IDLE) return false; // We can't accept a commit if we have a pending tree. if (has_pending_tree_) return false; // We want to handle readback commits immediately to unblock the main thread. // Note: This BeginMainFrame will correspond to the replacement commit that // comes after the readback commit itself, so we only send the BeginMainFrame // if a commit isn't already pending behind the readback. if (readback_state_ == READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME) return !CommitPending(); // We do not need commits if we are not visible, unless there's a // request for a readback. if (!visible_) return false; // We want to start the first commit after we get a new output surface ASAP. if (output_surface_state_ == OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT) return true; // With deadline scheduling enabled, we should not send BeginMainFrame while // we are in BEGIN_IMPL_FRAME_STATE_IDLE, since we might have new user input // coming in soon. // However, if we are not expecting a BeginImplFrame to take us out of idle, // we should not early out here to avoid blocking commits forever. // This only works well when deadline scheduling is enabled because there is // an interval over which to accept the commit and draw. Without deadline // scheduling, delaying the commit could prevent us from having something // to draw on the next BeginImplFrame. // TODO(brianderson): Allow sending BeginMainFrame while idle when the main // thread isn't consuming user input. if (settings_.deadline_scheduling_enabled && begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_IDLE && BeginImplFrameNeeded()) 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. if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_COMMIT) return true; // After this point, we only start a commit once per frame. if (HasSentBeginMainFrameThisFrame()) return false; // We shouldn't normally accept commits if there isn't an OutputSurface. if (!HasInitializedOutputSurface()) return false; if (skip_begin_main_frame_to_reduce_latency_) return false; return true; } bool SchedulerStateMachine::ShouldCommit() const { return commit_state_ == COMMIT_STATE_READY_TO_COMMIT; } bool SchedulerStateMachine::IsCommitStateWaiting() const { return commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS; } bool SchedulerStateMachine::ShouldManageTiles() const { // ManageTiles only really needs to be called immediately after commit // and then periodically after that. Limiting to once per frame prevents // post-commit and post-draw ManageTiles on the same frame. if (last_frame_number_manage_tiles_called_ == current_frame_number_) return false; // Limiting to once per-frame is not enough, since we only want to // manage tiles _after_ draws. Polling for draw triggers and // begin-frame are mutually exclusive, so we limit to these two cases. if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE && !inside_poll_for_anticipated_draw_triggers_) return false; return needs_manage_tiles_; } SchedulerStateMachine::Action SchedulerStateMachine::NextAction() const { if (ShouldAcquireLayerTexturesForMainThread()) return ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD; if (ShouldUpdateVisibleTiles()) return ACTION_UPDATE_VISIBLE_TILES; if (ShouldActivatePendingTree()) return ACTION_ACTIVATE_PENDING_TREE; if (ShouldCommit()) return ACTION_COMMIT; if (ShouldDraw()) { if (readback_state_ == READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK) return ACTION_DRAW_AND_READBACK; else 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 (ShouldManageTiles()) return ACTION_MANAGE_TILES; if (ShouldSendBeginMainFrame()) return ACTION_SEND_BEGIN_MAIN_FRAME; if (ShouldBeginOutputSurfaceCreation()) return ACTION_BEGIN_OUTPUT_SURFACE_CREATION; return ACTION_NONE; } void SchedulerStateMachine::CheckInvariants() { // We should never try to perform a draw for readback and forced draw due to // timeout simultaneously. DCHECK(!(forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW && readback_state_ == READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK)); } void SchedulerStateMachine::UpdateState(Action action) { switch (action) { case ACTION_NONE: return; case ACTION_UPDATE_VISIBLE_TILES: last_frame_number_update_visible_tiles_was_called_ = current_frame_number_; return; case ACTION_ACTIVATE_PENDING_TREE: UpdateStateOnActivation(); return; case ACTION_SEND_BEGIN_MAIN_FRAME: DCHECK(!has_pending_tree_); DCHECK(visible_ || readback_state_ == READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME); commit_state_ = COMMIT_STATE_FRAME_IN_PROGRESS; needs_commit_ = false; if (readback_state_ == READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME) readback_state_ = READBACK_STATE_WAITING_FOR_COMMIT; last_frame_number_begin_main_frame_sent_ = current_frame_number_; return; case ACTION_COMMIT: { bool commit_was_aborted = false; UpdateStateOnCommit(commit_was_aborted); return; } case ACTION_DRAW_AND_SWAP_FORCED: case ACTION_DRAW_AND_SWAP_IF_POSSIBLE: { bool did_swap = true; UpdateStateOnDraw(did_swap); return; } case ACTION_DRAW_AND_SWAP_ABORT: case ACTION_DRAW_AND_READBACK: { bool did_swap = false; UpdateStateOnDraw(did_swap); return; } case ACTION_BEGIN_OUTPUT_SURFACE_CREATION: 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(commit_state_, COMMIT_STATE_IDLE); DCHECK(!has_pending_tree_); DCHECK(!active_tree_needs_first_draw_); return; case ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD: texture_state_ = LAYER_TEXTURE_STATE_ACQUIRED_BY_MAIN_THREAD; main_thread_needs_layer_textures_ = false; return; case ACTION_MANAGE_TILES: UpdateStateOnManageTiles(); return; } } void SchedulerStateMachine::UpdateStateOnCommit(bool commit_was_aborted) { commit_count_++; // If we are impl-side-painting but the commit was aborted, then we behave // mostly as if we are not impl-side-painting since there is no pending tree. has_pending_tree_ = settings_.impl_side_painting && !commit_was_aborted; // Update state related to readbacks. if (readback_state_ == READBACK_STATE_WAITING_FOR_COMMIT) { // Update the state if this is the readback commit. readback_state_ = has_pending_tree_ ? READBACK_STATE_WAITING_FOR_ACTIVATION : READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK; } else if (readback_state_ == READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT) { // Update the state if this is the commit replacing the readback commit. readback_state_ = has_pending_tree_ ? READBACK_STATE_WAITING_FOR_REPLACEMENT_ACTIVATION : READBACK_STATE_IDLE; } else { DCHECK(readback_state_ == READBACK_STATE_IDLE); } // Readbacks can interrupt output surface initialization and forced draws, // so we do not want to advance those states if we are in the middle of a // readback. Note: It is possible for the readback's replacement commit to // be the output surface's first commit and/or the forced redraw's commit. if (readback_state_ == READBACK_STATE_IDLE || readback_state_ == READBACK_STATE_WAITING_FOR_REPLACEMENT_ACTIVATION) { // 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; needs_redraw_ = true; } } } // Update the commit state. We expect and wait for a draw if the commit // was not aborted or if we are in a readback or forced draw. if (!commit_was_aborted) { DCHECK(commit_state_ == COMMIT_STATE_READY_TO_COMMIT); commit_state_ = COMMIT_STATE_WAITING_FOR_FIRST_DRAW; } else if (readback_state_ != READBACK_STATE_IDLE || forced_redraw_state_ != FORCED_REDRAW_STATE_IDLE) { commit_state_ = COMMIT_STATE_WAITING_FOR_FIRST_DRAW; } else { commit_state_ = COMMIT_STATE_IDLE; } // Update state if we have a new active tree to draw, or if the active tree // was unchanged but we need to do a readback or forced draw. if (!has_pending_tree_ && (!commit_was_aborted || readback_state_ == READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK || forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW)) { 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; if (draw_if_possible_failed_) last_frame_number_swap_performed_ = -1; // If we are planing to draw with the new commit, lock the layer textures for // use on the impl thread. Otherwise, leave them unlocked. if (has_pending_tree_ || needs_redraw_) texture_state_ = LAYER_TEXTURE_STATE_ACQUIRED_BY_IMPL_THREAD; else texture_state_ = LAYER_TEXTURE_STATE_UNLOCKED; } void SchedulerStateMachine::UpdateStateOnActivation() { // Update output surface state. if (output_surface_state_ == OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION) output_surface_state_ = OUTPUT_SURFACE_ACTIVE; // Update readback state if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_ACTIVATION) forced_redraw_state_ = FORCED_REDRAW_STATE_WAITING_FOR_DRAW; // Update forced redraw state if (readback_state_ == READBACK_STATE_WAITING_FOR_ACTIVATION) readback_state_ = READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK; else if (readback_state_ == READBACK_STATE_WAITING_FOR_REPLACEMENT_ACTIVATION) readback_state_ = READBACK_STATE_IDLE; has_pending_tree_ = false; pending_tree_is_ready_for_activation_ = false; active_tree_needs_first_draw_ = true; needs_redraw_ = true; } void SchedulerStateMachine::UpdateStateOnDraw(bool did_swap) { DCHECK(readback_state_ != READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT && readback_state_ != READBACK_STATE_WAITING_FOR_REPLACEMENT_ACTIVATION) << *AsValue(); if (readback_state_ == READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK) { // The draw correspons to a readback commit. DCHECK_EQ(commit_state_, COMMIT_STATE_WAITING_FOR_FIRST_DRAW); // We are blocking commits from the main thread until after this draw, so // we should not have a pending tree. DCHECK(!has_pending_tree_); // We transition to COMMIT_STATE_FRAME_IN_PROGRESS because there is a // pending BeginMainFrame behind the readback request. commit_state_ = COMMIT_STATE_FRAME_IN_PROGRESS; readback_state_ = READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT; } else if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_DRAW) { DCHECK_EQ(commit_state_, COMMIT_STATE_WAITING_FOR_FIRST_DRAW); commit_state_ = COMMIT_STATE_IDLE; forced_redraw_state_ = FORCED_REDRAW_STATE_IDLE; } else if (commit_state_ == COMMIT_STATE_WAITING_FOR_FIRST_DRAW && !has_pending_tree_) { commit_state_ = COMMIT_STATE_IDLE; } if (texture_state_ == LAYER_TEXTURE_STATE_ACQUIRED_BY_IMPL_THREAD) texture_state_ = LAYER_TEXTURE_STATE_UNLOCKED; needs_redraw_ = false; draw_if_possible_failed_ = false; active_tree_needs_first_draw_ = false; if (did_swap) last_frame_number_swap_performed_ = current_frame_number_; } void SchedulerStateMachine::UpdateStateOnManageTiles() { needs_manage_tiles_ = false; } void SchedulerStateMachine::SetMainThreadNeedsLayerTextures() { DCHECK(!main_thread_needs_layer_textures_); DCHECK_NE(texture_state_, LAYER_TEXTURE_STATE_ACQUIRED_BY_MAIN_THREAD); main_thread_needs_layer_textures_ = true; } void SchedulerStateMachine::SetSkipBeginMainFrameToReduceLatency(bool skip) { skip_begin_main_frame_to_reduce_latency_ = skip; } bool SchedulerStateMachine::BeginImplFrameNeeded() const { // Proactive BeginImplFrames are bad for the synchronous compositor because we // have to draw when we get the BeginImplFrame and could end up drawing many // duplicate frames if our new frame isn't ready in time. // To poll for state with the synchronous compositor without having to draw, // we rely on ShouldPollForAnticipatedDrawTriggers instead. if (!SupportsProactiveBeginImplFrame()) return BeginImplFrameNeededToDraw(); return BeginImplFrameNeededToDraw() || ProactiveBeginImplFrameWanted(); } bool SchedulerStateMachine::ShouldPollForAnticipatedDrawTriggers() const { // ShouldPollForAnticipatedDrawTriggers is what we use in place of // ProactiveBeginImplFrameWanted when we are using the synchronous // compositor. if (!SupportsProactiveBeginImplFrame()) { return !BeginImplFrameNeededToDraw() && ProactiveBeginImplFrameWanted(); } // Non synchronous compositors should rely on // ProactiveBeginImplFrameWanted to poll for state instead. return false; } bool SchedulerStateMachine::SupportsProactiveBeginImplFrame() const { // Both the synchronous compositor and disabled vsync settings // make it undesirable to proactively request BeginImplFrames. // If this is true, the scheduler should poll. return !settings_.using_synchronous_renderer_compositor && settings_.throttle_frame_production; } // These are the cases where we definitely (or almost definitely) have a // new frame to draw and can draw. bool SchedulerStateMachine::BeginImplFrameNeededToDraw() const { // The output surface is the provider of BeginImplFrames, so we are not going // to get them even if we ask for them. if (!HasInitializedOutputSurface()) return false; // If we can't draw, don't tick until we are notified that we can draw again. if (!can_draw_) return false; // 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; // There's no need to produce frames if we are not visible. if (!visible_) return false; // We need to draw a more complete frame than we did the last BeginImplFrame, // so request another BeginImplFrame in anticipation that we will have // additional visible tiles. if (swap_used_incomplete_tile_) return true; return needs_redraw_; } // These are cases where we are very likely to draw soon, but might not // actually have a new frame to draw when we receive the next BeginImplFrame. // Proactively requesting the BeginImplFrame helps hide the round trip latency // of the SetNeedsBeginImplFrame request that has to go to the Browser. bool SchedulerStateMachine::ProactiveBeginImplFrameWanted() const { // The output surface is the provider of BeginImplFrames, // so we are not going to get them even if we ask for them. if (!HasInitializedOutputSurface()) return false; // 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. if (needs_commit_ || commit_state_ != COMMIT_STATE_IDLE) 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_manage_tiles_) return true; // If we just swapped, it's likely that we are going to produce another // frame soon. This helps avoid negative glitches in our // SetNeedsBeginImplFrame requests, which may propagate to the BeginImplFrame // provider and get sampled at an inopportune time, delaying the next // BeginImplFrame. if (last_frame_number_swap_performed_ == current_frame_number_) return true; return false; } void SchedulerStateMachine::OnBeginImplFrame(const BeginFrameArgs& args) { current_frame_number_++; last_begin_impl_frame_args_ = args; DCHECK_EQ(begin_impl_frame_state_, BEGIN_IMPL_FRAME_STATE_IDLE) << *AsValue(); begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING; } void SchedulerStateMachine::OnBeginImplFrameDeadlinePending() { DCHECK_EQ(begin_impl_frame_state_, BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING) << *AsValue(); begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME; } void SchedulerStateMachine::OnBeginImplFrameDeadline() { DCHECK_EQ(begin_impl_frame_state_, BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME) << *AsValue(); begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE; } void SchedulerStateMachine::OnBeginImplFrameIdle() { DCHECK_EQ(begin_impl_frame_state_, BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE) << *AsValue(); begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_IDLE; } bool SchedulerStateMachine::ShouldTriggerBeginImplFrameDeadlineEarly() const { // TODO(brianderson): This should take into account multiple commit sources. // If we are in the middle of the readback, we won't swap, so there is // no reason to trigger the deadline early. if (readback_state_ != READBACK_STATE_IDLE) return false; if (begin_impl_frame_state_ != BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME) 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 (commit_state_ == COMMIT_STATE_IDLE && !has_pending_tree_) return true; // Prioritize impl-thread draws in smoothness mode. if (smoothness_takes_priority_) return true; return false; } bool SchedulerStateMachine::MainThreadIsInHighLatencyMode() const { // If we just sent a BeginMainFrame and haven't hit the deadline yet, the main // thread is in a low latency mode. if (last_frame_number_begin_main_frame_sent_ == current_frame_number_ && (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING || begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME)) return false; // If there's a commit in progress it must either be from the previous frame // or it started after the impl thread's deadline. In either case the main // thread is in high latency mode. if (commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS || commit_state_ == COMMIT_STATE_READY_TO_COMMIT) return true; // Similarly, if there's a pending tree the main thread is in high latency // mode, because either // it's from the previous frame // or // we're currently drawing the active tree and the pending tree will thus // only be drawn in the next frame. if (has_pending_tree_) return true; if (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE) { // Even if there's a new active tree to draw at the deadline or we've just // drawn it, it may have been triggered by a previous BeginImplFrame, in // which case the main thread is in a high latency mode. return (active_tree_needs_first_draw_ || last_frame_number_swap_performed_ == current_frame_number_) && last_frame_number_begin_main_frame_sent_ != current_frame_number_; } // If the active tree needs its first draw in any other state, we know the // main thread is in a high latency mode. return active_tree_needs_first_draw_; } void SchedulerStateMachine::DidEnterPollForAnticipatedDrawTriggers() { current_frame_number_++; inside_poll_for_anticipated_draw_triggers_ = true; } void SchedulerStateMachine::DidLeavePollForAnticipatedDrawTriggers() { inside_poll_for_anticipated_draw_triggers_ = false; } void SchedulerStateMachine::SetVisible(bool visible) { visible_ = visible; } void SchedulerStateMachine::SetCanDraw(bool can_draw) { can_draw_ = can_draw; } void SchedulerStateMachine::SetNeedsRedraw() { needs_redraw_ = true; } void SchedulerStateMachine::SetNeedsManageTiles() { if (!needs_manage_tiles_) { TRACE_EVENT0("cc", "SchedulerStateMachine::SetNeedsManageTiles"); needs_manage_tiles_ = true; } } void SchedulerStateMachine::SetSwapUsedIncompleteTile( bool used_incomplete_tile) { swap_used_incomplete_tile_ = used_incomplete_tile; } void SchedulerStateMachine::SetSmoothnessTakesPriority( bool smoothness_takes_priority) { smoothness_takes_priority_ = smoothness_takes_priority; } void SchedulerStateMachine::DidDrawIfPossibleCompleted(bool success) { draw_if_possible_failed_ = !success; if (draw_if_possible_failed_) { 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_commit_ = true; consecutive_failed_draws_++; if (settings_.timeout_and_draw_when_animation_checkerboards && consecutive_failed_draws_ >= settings_.maximum_number_of_failed_draws_before_draw_is_forced_) { consecutive_failed_draws_ = 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; } } else { consecutive_failed_draws_ = 0; forced_redraw_state_ = FORCED_REDRAW_STATE_IDLE; } } void SchedulerStateMachine::SetNeedsCommit() { needs_commit_ = true; } void SchedulerStateMachine::SetNeedsForcedCommitForReadback() { // If this is called in READBACK_STATE_IDLE, this is a "first" readback // request. // If this is called in READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT, this // is a back-to-back readback request that started before the replacement // commit had a chance to land. DCHECK(readback_state_ == READBACK_STATE_IDLE || readback_state_ == READBACK_STATE_WAITING_FOR_REPLACEMENT_COMMIT); // If there is already a commit in progress when we get the readback request // (we are in COMMIT_STATE_FRAME_IN_PROGRESS), then we don't need to send a // BeginMainFrame for the replacement commit, since there's already a // BeginMainFrame behind the readback request. In that case, we can skip // READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME and go directly to // READBACK_STATE_WAITING_FOR_COMMIT if (commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS) readback_state_ = READBACK_STATE_WAITING_FOR_COMMIT; else readback_state_ = READBACK_STATE_NEEDS_BEGIN_MAIN_FRAME; } void SchedulerStateMachine::FinishCommit() { DCHECK(commit_state_ == COMMIT_STATE_FRAME_IN_PROGRESS) << *AsValue(); commit_state_ = COMMIT_STATE_READY_TO_COMMIT; } void SchedulerStateMachine::BeginMainFrameAborted(bool did_handle) { DCHECK_EQ(commit_state_, COMMIT_STATE_FRAME_IN_PROGRESS); if (did_handle) { bool commit_was_aborted = true; UpdateStateOnCommit(commit_was_aborted); } else { DCHECK_NE(readback_state_, READBACK_STATE_WAITING_FOR_COMMIT); commit_state_ = COMMIT_STATE_IDLE; SetNeedsCommit(); } } void SchedulerStateMachine::DidManageTiles() { needs_manage_tiles_ = false; last_frame_number_manage_tiles_called_ = current_frame_number_; } 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; begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_IDLE; } void SchedulerStateMachine::NotifyReadyToActivate() { if (has_pending_tree_) pending_tree_is_ready_for_activation_ = true; } 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_commit_ = true; } did_create_and_initialize_first_output_surface_ = true; } 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