blob: a8daa03bf53a29fd5f0232a560ccc972c9bcfa56 [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 <algorithm>
#include <cstdint>
#include <memory>
#include <string>
#include <unordered_map>
#include "base/gtest_prod_util.h"
#include "base/sequence_checker.h"
#include "base/time/time.h"
#include "chrome/browser/resource_coordinator/time.h"
#include "chrome/browser/sessions/session_restore_observer.h"
namespace content {
class SwapMetricsDriver;
class WebContents;
} // namespace content
namespace resource_coordinator {
// TabManagerStatsCollector records UMAs on behalf of TabManager for tab and
// system-related events and properties during session restore or background tab
// opening session.
class TabManagerStatsCollector final : public SessionRestoreObserver {
enum SessionType {
// SessionRestore is the duration from the time when the browser starts to
// restore tabs until the time when the browser has finished loading those
// tabs or when the browser stops loading tabs due to memory pressure.
// During SessionRestore, some other tabs could be open due to user action,
// but that would not affect the session end time point. For example, a
// browser starts to restore tab1 and tab2. Tab3 is open due to user
// clicking a link in tab1. SessionRestore ends after tab1 and tab2 finishes
// loading, even if tab3 is still loading.
// BackgroundTabOpening session is the duration from the time when the
// browser starts to open background tabs until the time when browser has
// finished loading those tabs or paused loading due to memory pressure.
// A new session starts when the browser resumes loading background tabs
// when memory pressure returns to normal. During the BackgroundTabOpening
// session, some background tabs could become foreground due to user action,
// but that would not affect the session end time point. For example, a
// browser has tab1 in foreground, and starts to open tab2 and tab3 in
// background. The session will end after tab2 and tab3 finishes loading,
// even if tab2 and tab3 are brought to foreground before they are loaded.
// BackgroundTabOpening session excludes the background tabs being
// controlled by SessionRestore, so that those two activities are clearly
// separated.
// Houses all of the background tab count statistics gathered by
// TabManagerStatsCollector for background tab opening.
struct BackgroundTabCountStats {
// Reset everything to zero. This is called when a background tab opening
// session starts.
void Reset();
// The max number of background tabs pending or loading in a background
// tab opening session.
size_t tab_count;
// The max number of background tabs that were paused to load in a
// background tab opening session due to memory pressure.
size_t tab_paused_count;
// The number of background tabs whose loading was triggered by TabManager
// automatically.
size_t tab_load_auto_started_count;
// The number of background tabs whose loading was triggered by user
// selection.
size_t tab_load_user_initiated_count;
// Records histograms *before* starting to urgently discard LifecycleUnits.
// |num_alive_tabs| is the number of tabs that are not pending load or
// discarded.
void RecordWillDiscardUrgently(int num_alive_tabs);
// Records UMA histograms for the tab state when switching to a different tab
// during session restore.
void RecordSwitchToTab(content::WebContents* old_contents,
content::WebContents* new_contents);
// Record expected task queueing durations of foreground tabs in session
// restore.
void RecordExpectedTaskQueueingDuration(content::WebContents* contents,
base::TimeDelta queueing_time);
// Record background tab count for BackgroundTabOpening.
void RecordBackgroundTabCount();
// SessionRestoreObserver
void OnSessionRestoreStartedLoadingTabs() override;
void OnSessionRestoreFinishedLoadingTabs() override;
// The following two functions defines the start and end of a background tab
// opening session.
void OnBackgroundTabOpeningSessionStarted();
void OnBackgroundTabOpeningSessionEnded();
// Track background tabs and update background tab count stats.
void TrackNewBackgroundTab(size_t pending_tabs, size_t loading_tabs) {
background_tab_count_stats_.tab_count = std::max(
background_tab_count_stats_.tab_count, pending_tabs + loading_tabs + 1);
void TrackPausedBackgroundTabs(size_t paused_tabs) {
background_tab_count_stats_.tab_paused_count =
std::max(background_tab_count_stats_.tab_paused_count, paused_tabs);
void TrackBackgroundTabLoadAutoStarted() {
void TrackBackgroundTabLoadUserInitiated() {
// Record UMA histograms for system swap metrics.
void RecordSwapMetrics(SessionType type,
const std::string& metric_name,
uint64_t count,
base::TimeDelta interval);
// Handles the situation when failing to update swap metrics.
void OnUpdateSwapMetricsFailed();
// Called by WebContentsData when a tab starts loading. Used to clean up
// |foreground_contents_switched_to_times_| if we were tracking this tab and
// OnDidStopLoading has not yet been called for it, which will happen if the
// user navigates to a new page and |contents| is resused.
void OnDidStartMainFrameNavigation(content::WebContents* contents);
// Called by TabManager when it decides to load the next tab. Used as the
// signal to record how often timeout happens. Timeout means it wants to start
// loading the next tab even though the previous tab is still loading.
void OnWillLoadNextBackgroundTab(bool timeout);
// Called by TabManager when a tab is considered loaded. Used as the signal to
// record tab switch load time metrics for |contents|.
void OnTabIsLoaded(content::WebContents* contents);
// Called by TabManager when a WebContents is destroyed. Used to clean up
// |foreground_contents_switched_to_times_| if we were tracking this tab and
// OnDidStopLoading has not yet been called for it.
void OnWebContentsDestroyed(content::WebContents* contents);
bool is_in_background_tab_opening_session() const {
return is_in_background_tab_opening_session_;
class SwapMetricsDelegate;
// Returns true if the browser is currently in more than one session with
// different types. We do not want to report metrics in this situation to have
// meaningful results. For example, SessionRestore and BackgroundTabOpening
// session could overlap.
bool IsInOverlappedSession();
// This is called when we enter overlapped session. We need to clear all stats
// in such situation to avoid reporting mixed metric results.
void ClearStatsWhenInOverlappedSession();
// Create and initialize the swap metrics driver if needed. This will set the
// driver to null when it is in overlapped session situation, so that we do
// not report swap metrics.
void CreateAndInitSwapMetricsDriverIfNeeded(SessionType type);
// Update session and sequence information for UKM recording.
void UpdateSessionAndSequence();
static const char
static const char
static const char kHistogramSessionRestoreSwitchToTab[];
static const char kHistogramBackgroundTabOpeningSwitchToTab[];
static const char kHistogramSessionRestoreTabSwitchLoadTime[];
static const char kHistogramBackgroundTabOpeningTabSwitchLoadTime[];
static const char kHistogramBackgroundTabOpeningTabCount[];
static const char kHistogramBackgroundTabOpeningTabPausedCount[];
static const char kHistogramBackgroundTabOpeningTabLoadAutoStartedCount[];
static const char kHistogramBackgroundTabOpeningTabLoadUserInitiatedCount[];
static const char kHistogramBackgroundTabOpeningTabLoadTimeout[];
static const char kHistogramSessionOverlapSessionRestore[];
static const char kHistogramSessionOverlapBackgroundTabOpening[];
// TabManagerStatsCollector should be used from a single sequence.
// Time at which the TabManagerStatsCollector was created.
const base::TimeTicks start_time_ = NowTicks();
// Last time at which TabManager had to urgently discard LifecycleUnits.
base::TimeTicks last_urgent_discard_time_;
int session_id_ = -1;
int sequence_ = 0;
bool is_session_restore_loading_tabs_ = false;
bool is_in_background_tab_opening_session_ = false;
bool is_overlapping_session_restore_ = false;
bool is_overlapping_background_tab_opening_ = false;
// This is shared between SessionRestore and BackgroundTabOpening because we
// do not report metrics when those two overlap.
std::unique_ptr<content::SwapMetricsDriver> swap_metrics_driver_;
// The set of foreground tabs during session restore or background tab opening
// sessions that were switched to have not yet finished loading, mapped to the
// time that they were switched to. It's possible to have multiple background
// opening sessions or session restores happening simultaneously in different
// windows, which means there can be multiple foreground tabs that have been
// switched to that haven't finished loading. Because of that, we need to
// track each foreground tab and its corresponding switch-to time.
std::unordered_map<content::WebContents*, base::TimeTicks>
BackgroundTabCountStats background_tab_count_stats_;
} // namespace resource_coordinator