anthonyvd@chromium.org catan-team@chromium.org True if the CPU estimation task was running on a different CPU at the end of the assembly loop than it was at the beginning. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. anthonyvd@chromium.org catan-team@chromium.org The time in microseconds during which the CPU estimation task was queued before running. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. Reported only on devices using the high resolution clock. anthonyvd@chromium.org catan-team@chromium.org The thread time in microseconds it took to fully execute the CPU estimation task. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. Reported only on devices using the high resolution clock. anthonyvd@chromium.org catan-team@chromium.org The time in microseconds it took to fully execute the CPU estimation task, that is its queued time + the wall time elapsed before the task finished. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. Reported only on devices using the high resolution clock. anthonyvd@chromium.org catan-team@chromium.org The wall time in microseconds it took to fully execute the CPU estimation task. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. Reported only on devices using the high resolution clock. anthonyvd@chromium.org catan-team@chromium.org The ratio of thread time vs wall time of the CPU estimation task's "running" portion, i.e. the thread time of the assembly loop divided by its wall time. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. anthonyvd@chromium.org catan-team@chromium.org The CPU frequency as a percentage of the estimated current frequency (see base::EstimateCpuFrequency) over the max frequency of the fastest CPU, as reported by base::GetCpuMhzLimit. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. anthonyvd@chromium.org catan-team@chromium.org The CPU frequency as a percentage of the estimated current frequency (see base::EstimateCpuFrequency) over the max frequency of the fastest CPU, as reported by base::GetCpuMaxMhz. Recorded when the CPU estimation task runs (every 5 minutes). Windows x86 only. aattar@google.com chrome-catan@google.com Recorded every time the DiscardEligibilityPolicy evaluates a tab for discarding. Tracks whether the tab was Eligible, Protected (blocked by policy), or Disallowed. This metric is recorded for all decisions, and broken down by the {Trigger} reason. aattar@google.com chrome-catan@google.com Recorded at the moment a discard decision is made. This is recorded at the same time as PerformanceManager.Discarding.DecisionResult. Indicates if the tab had recorded form interactions. aattar@google.com chrome-catan@google.com Recorded at the moment a discard decision is made. This is recorded at the same time as PerformanceManager.Discarding.DecisionResult. Indicates if the tab had recorded user edits (typing). aattar@google.com chrome-catan@google.com Recorded when a tab is marked as 'Protected' during a discard evaluation. This is recorded at the same time as PerformanceManager.Discarding.DecisionResult. Logs the specific reason (e.g., Audio, Form Interaction, Pinned) that prevented the discard. aattar@google.com chrome-catan@google.com Recorded at the moment a discard decision is made. This is recorded at the same time as PerformanceManager.Discarding.DecisionResult. Measures how long the tab has been hidden (in background). Short durations here correlate with high user regret. anthonyvd@chromium.org chrome-catan@google.com The amount of available space in megabytes on the disk that hosts the current user data directory as reported by SysInfo::AmountOfFreeDiskSpace(user_data_dir). Warning: this histogram was expired from 2025-02-16 to 2025-03-20; data may be missing. anthonyvd@chromium.org chrome-catan@google.com The percentage of available space on the disk that hosts the current user data directory as reported by SysInfo::AmountOfFreeDiskSpace(user_data_dir) / capacity. anthonyvd@chromium.org chrome-catan@google.com Whether individual accessibility mode flags are set. Recorded with every UMA report to attempt to slice other metrics based on which a11y flags are set. anthonyvd@chromium.org chrome-catan@google.com Whether any accessibility mode flags are set. Recorded with every UMA report to attempt to slice other metrics based on whether a11y is active. kraskevich@google.com chrome-catan@google.com Logged whenever the Performance Manager input scenario changes away from {InputScenario}, with the reason for the change. fdoray@chromium.org chrome-catan@google.com The outcome of attempting to read the value of the HKEY_LOCAL_MACHINE : Software\Microsoft\Windows NT\CurrentVersion\Image File : FrontEndHeapDebugOptions registry key. Emitted when UMA requests information about the current session (see metrics::MetricsProvider::ProvideCurrentSessionData). fdoray@chromium.org chrome-catan@google.com The value of the HKEY_LOCAL_MACHINE : Software\Microsoft\Windows NT\CurrentVersion\Image File : FrontEndHeapDebugOptions registry key. Emitted every time kSuccess is reported to PerformanceManager.RegistryStats.FrontEndHeapDebugOptionsOutcome. joenotcharles@google.com olivierli@chromium.org chrome-catan@google.com The time it takes for a single Resource Attribution query to return results. This slice of the metric covers the {Function} function. anthonyvd@chromium.org chrome-catan@google.com Logged everytime a background tab is closed. Records the time in seconds that the tab has spent in the background since it was last active. anthonyvd@chromium.org chrome-catan@google.com Logged everytime a background tab is revisited. Records the time in seconds that the tab has spent in the background since it was last active. aattar@google.com chrome-catan@google.com Recorded when a renderer process's transient keep-alive is resolved. This tracks the final state of the keep-alive attempt, corresponding to the TransientKeepAliveResult enum (e.g., successful reuse, eviction, or timeout). aattar@google.com chrome-catan@google.com Recorded only when a process kept alive by the TransientKeepAlivePolicy was successfully reused (i.e., when TransientKeepAliveResult::kReused is recorded in the .Result histogram). Measures the time delta from when the process became empty (and the keep-alive timer started) to when it was reused for a new navigation. anthonyvd@chromium.org chrome-catan@google.com Recorded every UMA upload, this histogram represents the percentage of the interval since the last upload that was spent with Battery Saver enabled. anthonyvd@chromium.org chrome-catan@google.com Logged on each UMA upload to represent which user-controllable Efficiency Mode setting the browser is in during the reported window. If the mode was changed between uploads, MIXED will be reported for that interval. This histogram is used internally to filter other histograms by efficiency mode. anthonyvd@chromium.org chrome-catan@google.com Recorded every UMA upload, this histogram represents the percentage of the interval since the last upload that was spent with Memory Saver enabled.