Unreleased:
  Tracing service and probes:
    *
  Trace Processor:
    *
  UI:
    * Fixed ADB connection issues ("unable to reset device") on Windows and Mac.
  SDK:
    * Added support for writing track events using custom clock timestamps.


v16.0 - 2021-06-01:
  Tracing service and probes:
    * Added support for building most targets (including traced, SDK and
      trace_processor_shell) from Windows using either clang-cl or MSVC 2019.
    * Added tracebox, a monolithic binary to capture traces with one command
      on Linux and older versions of Android (tested on Android Oreo).
    * Added support for service-side field-level filtering of traces. The
      consumer can pass a filter bytecode and ensure that non-allowed fields
      are never emitted in output.
    * Added reporting of service version and producer SDK version into the trace
      and `perfetto --query`.
    * Fixed compatibility with Android versions older than Pie (for sideloading)
      which cause failures when trying to enable atrace categories.
  Trace Processor:
    * Added new RPC interface based on a bidirectional binary pipe. This allows
      to simplify integration with out-of-process users. The existing --httpd
      interface now exposes a single /rpc endpoint. Older endpoints are still
      available for legacy clients.
    * Added support for counters and instant events in JSON traces.
    * Fixed support of displayTimeUnit in JSON traces.
  UI:
    * Added warning dialog when trying to use a trace_processor_shell --httpd
      which is too old.
    * Added warning dialog when trying to use a trace_processor_shell --httpd
      RPC instance from more than one tab.
    * Added links to convert the trace to JSON or systrace directly from the UI.
    * Changed track sorting logic. Tracks are now sorted in groups (e.g.,
      scheduling tracks, summary tracks, frame timeline tracks).
    * Fixed crashes happening flakily when pushing traces via window.open().


v15.0 - 2021-05-05:
  Tracing service and probes:
    * Added support for {host,target}=aarch64 standalone builds.
    * Added --background cmdline switch to traced and traced_probes services.
    * Changed trigger_perfetto to ignore unknown command line arguments to
      preserve forward compatibility.
    * Added -a / --app cmdline argument to tools/record_android_trace.
  Trace Processor:
    * Added sanitisation of keys in nested debug annotation dictionaries.
    * Changed Android startup metric: count CPU time of JIT thread pool, report
      timestamp of activities during startup.
    * Changed android_surfaceflinger metric, added missed frame counters.
    * Changed version of SQLite to 3.35.4.
    * Fixed importing of JSON traces with decimal (sub-us) timestamp.
    * Fixed prepending "debug." prefix to debug annotations with non-interned
      names.
  UI:
    * Added support to visualize the lifetime of individual dmabuf allocations
      as async slices (datasource: already existing ftrace dmabuf event).
    * Fixed visualization of unfinished slices to extend to the end of the
      viewport.
  SDK:
    * Added support for passing arbitrary number of debug annotations to
      TRACE_EVENT and combining them with lambdas.
    * Added support for writing typed TrackEvent arguments using TRACE_EVENT
      inline without lambdas.
    * Changed ConvertTimestampToTraceTimeNs to be a member of
      TraceTimestampTraits<T> struct instead of a standalone function.
    * Changed TracedValue to use nested DebugAnnotation proto instead of
      DebugAnnotation::NestedValue.


v14.0 - 2021-04-01:
  Tracing service and probes:
    * Added support for polling power rails on Android from the newer
      IPowerStats AIDL interface (previously using only the HAL interface).
    * Fixed native heap profiler crash when ABI of heapprofd and profiled
      process mismatch.
    * Changed encoding format of Anroid managed heap profiler to reduce heap
      dump sizes by delta-encoding object IDs.
  Trace Processor:
    * Added activity create/resume, layout inflation and resource timings to
      the Android startup metric.
    * Added chrome metadata key/value pairs (e.g. chrome version) into the
      `metadata` table with 'cr-' prefixed keys.
    * Added dma-buf-based memory metrics reporting total/avg/min/max dmabuf
      allocation per-dmabuf-heap and per-process.
    * Removed |force_full_sort| flag from config. This has been replaced
      by setting the sorting mode to force a full sort.
  UI:
    * Added tools/symbolize-ui-crash script to resolve crash reports via
      TypeScript source maps.
    * Fixed newlines when copying Android event log lines into the clipboard.
    * Fixed crash when selecting "Did not finish" slices.
    * Fixed OOM dialog to give actionable instructions when opening large traces
      rather than suggesting to file a bug.
  SDK:
    * Added /meson.build for bundling /sdk/perfetto.{cc,h} in Meson builds.
    * Added support for counter trace points with the TRACE_COUNTER macro.


v13.0 - 2021-03-01:
  Tracing service and probes:
    * Added ability to sample callstacks using kernel tracepoints as timebase.
    * Added abililty to record the perf timebase counter values into the trace,
      both combined callstack+counter or counter-only.
    * Added abillity to trigger traces based on VM pressure on Android. Requires
      a dedicated tracing instance in $tracefs/instances/mm_events.
  Trace Processor:
    * Added sorting mode to trace processor config to specify how trace
      processor should sort events. The |force_full_sort| flag has been
      deprecated (with replacement) and will be removed in the next version.
    * Added ingestion of frame timeline events into the
      {expected,actual}_frame_timeline_slice tables.
    * Added support for Mali's trace_marker_write ftrace event.
    * Added memory metric based on newer android_fastrpc kernel events.
  UI:
    * Added flow events support for instant events and async tracks.
    * Added support for Android frame timeline events. They allow inspecting
      end-to-end expected vs actual app-to-surfaceflinger frame times.
    * Added ability to switch between Canary and Stable channels in the UI.
    * Added ability to drag&drop to open trace files.
    * Changed UI serving infrastructure, old ui versions can be now retrieved by
      directly opening https://ui.perfetto.dev/v12.1.269/ .
    * Removed thread state track for threads that have no activity.
  SDK:
    * Use process start time hashed with the process id as a unique process
      identifier, allowing multiple independent users of the SDK in the same
      process to interleave their events on shared tracks.
    * Record process and thread names into the trace.
    * Add ring buffer tracing support, i.e., periodic clearing of incremental
      state.
  Misc:
    * Convert python scripts to python3.


v12.1 - 2021-02-01:
  Misc:
    * Fixed CHANGELOG which was missed in the 12.0 branch cut, causing
      mis-labeling of the version code in the v12.x branch as v11.0..N


v12.0 - 2021-02-01:
  Tracing service and probes:
    * Added more helpful error messages if the client library is used without
      having been initialized.
    * Added //tools/record_android_trace script to facilitate recording traces
      from Android devices, automating start + stop-via-ctrl+c + pull + open.
    * Added auto-attachment of traces to Android bugreports if dumpstate is
      invoked when a trace with bugreport_score > 0 is running.
  SDK:
    * Added ability to customize the timestamp of events via
      ConvertTimestampToTraceTimeNs().
    * Fixed support for category names that contain a space.
  Trace Processor:
    * Added ingestion and query support for Android end-to-end frame timing
      events through the {actual, expected}_frame_timeline_slice tables.
    * Added time-to-reportFullyDrawn (Android's API) to startup metrics.
    * Fixed excessive memory usage when decoding traces containing callstacks
      (https://github.com/google/perfetto/issues/83).
  UI:
    * Added ability to inspect the full trace config string from the
      'Info and stats' page.
    * Fixed 'TABLE/VIEW XXX already exists' in the Metrics page when running the
      same metric twice.
    * Fixed sorting of tracks using numeric sorting instead of lexicographic:
      Thread {1, 2, 10, 11, 20} rather than Thread {1, 10, 11, 2, 20}.
    * Fixed CSP-related bug that was preventing the UI to work on Firefox.
    * Changed max zoom resolution to allow to zoom to sub-us events.


v11.0 - 2021-01-01:
  Tracing service and probes:
    * Added trace packet interceptor API for rerouting trace data into
      non-Perfetto systems.
    * Added support for printing track events to the console.
    * Added a way to observe track event tracing sessions starting and
      stopping.
  Trace Processor:
    * Added "ancestor_slice" and "experimental_ancestor_stack_profile_callsite"
      table functions to look up ancestors of CPU stack samples in profiler
      tables.
    * Added power metric reporting suspend/resume time periods.
  UI:
    * Fixed CPU time calculation in example queries.
    * Added tracks to debug Android SystemUI jank.


v10.0 - 2020-12-01:
  Tracing service and probes:
    * Fixed crash of tracing service if a client is unresponsive on the IPC
      channel. Clients are disconnected if they don't respond to IPCs for 10s.
    * Added cmdline arguments for integration within ChromeOS system image
      (--{producer,consumer}-socket-{group,mode} for chmod-ing sockets).
    * Changed path lookup logic for traced socket. /run/perfetto/ is used if the
      directory exists, falling back on /tmp/ otherwise.
    * Added support for kernel frame symbolization to the traced_perf callstack
      sampler.
    * Added support for resolving ftrace event arguments that require
      symbolization against printk_format.
  Trace Processor:
    * Added .read command to inject a SQL query file, similar to the -q cmdline.
    * Added trace-based metrics to root cause jank in Android System UI.
    * Added symbolization support for ELF files on Windows for heap and
      callstack profilers.
    * Added support for symbolizing names of workqueue ftrace events.
    * Improved Android startup metric with activity restart time.
  UI:
    * Added support for navigating flows with Ctrl+[ / Ctr+].
    * Improved query result panel, moved to the bottom group allowing
      simultaneous query result and timeline views.
    * Fixed data corruption when recording traces via the WebUSB-based Record
      page in the UI.


v9.0 - 2020-11-01:
  Tracing service and probes:
    * Added support for recording traces from a system service through the
      client API.
    * The client library now reconnects producers automatically if the
      connection to the tracing service is lost. Also fixed crashes in ongoing
      tracing sessions when a disconnect occurs.
    * Added support for dpu and g2d ftrace events.
    * Enabled commit batching and producer side patching of chunks.
    * Add support for symbolizing kernel symbols for ftrace events.
  Trace Processor:
    * Fixed type affinity of string columns.
  UI:
    * Added initial support for running metrics from the UI.
    * Added support for displaying all flows when a slice or area is selected.
    * Highlight nodes that match the 'focus' string in the flamegraph.
    * Added search within slice args.
    * Fixed details panel height and moved query panel into details panel.
    * Enabled re-sharing of postMessage traces by echoing back the original URL.
    * Improved record page error messages.


v8.0 - 2020-10-01:
  Tracing service and probes:
    * Added API for querying registered data sources and their capabilities.
    * Added support for profiling heap allocations on Linux via LD_PRELOAD.
    * Fixed possible race when initializing the consumer library.
    * Fixed subtle bugs on systems with 16KB system pages.
  Trace Processor:
    * Added a table which lists available metrics.
    * Added Python bindings on PyPi in the 'perfetto' package.
    * Added support for running trace_processor_shell on Android.
    * Added per-process metrics for GPU memory usage.
    * Added support for exporting flow events to JSON.
    * Added dynamic tables for navigating between slices of flows.
  UI:
    * Changed time marking: horizontal selection doesn't gray out anymore,
      pressing 'm' marks the range.
    * Added initial support for displaying flow event arrows.
    * Improved ordering of all thread tracks under process grouping.
    * Fixed UI crashes due to metric errors
    * Fixed selection of thread state slices.


v7.0 - 2020-09-01:
  Tracing service and probes:
    * Added auto-reconnection to the SDK. Tracing::Initialize() now retries in
      the background, instead of failing, if the tracing service is unrechable.
    * Added support for recording cpuhp (CPU hotplug) ftrace events.
    * Fixed heap profiling unwinding on multi-ABI systems.
    * Fixed reporting of live objects in the native heap profiler when using
      --dump-at-max.
    * Fixed crash when writing trace events with field nesting level > 10.
  Trace Processor:
    * Added Python bindings, see
      https://perfetto.dev/docs/analysis/trace-processor#python-api .
    * Added ingestion for Chrome instant events and Chrome flow events.
    * Added ingestion for Android GPU memory events and sched_blocked_reason.
    * Added WebView power metric.
    * Added support for WSL1 where Async I/O is not available.
    * Improved detection of Android suspend/resume events.
  UI:
    * Added GPU memory recording controls and ingestion code. Requires a recent
      Android 12+ kernel.
    * Added details panel for flow events, showed when the user selects a slice
      involved in a flow (arrows in the UI are still being worked on).
    * Added instant events rendering.
    * Added Google Analytics.
    * Fixed I/O thread-states in 4.14 kernels to deal with the removal of
      wake-kill using sched_blocked_reason.
    * Fixed "Perfetto UI started debugging this browser" showing when opening
      the UI and the Chrome extension is installed.
  Misc:
    * Update language to comply with Android's inclusive language guidance.


v6.0 - 2020-08-01:
  Tracing service and probes:
    * Added ftrace thermal events.
    * Added support for custom allocators to the heap profiler. Allows
      developers to report memory allocations that are not done through malloc.
    * Added detailed timestamping of key tracing session events.
    * Added support for building tracing services on CrOS (system-wide tracing).
    * Fixed filtering out of stale ftrace data that predates the beginning of
      the tracing session.
  Trace Processor:
    * Improved profile symbolizer. PERFETTO_SYMBOLIZER_MODE=index discovers
      symbol files by build id rather than name.
    * Added screen-state Android metrics.
  UI:
    * Added 'Info and stats' page to debug data losses and trace stats.
    * Added full cmdline to process detail panel.
    * Improved performance of async tracks using quantized queries.
    * Improved performance of counter and slice tracks for long traces by
      pre-caching quantized track data.
    * Improved actionablility of crash dialog when the Wasm module OOMs.


v5.0 - 2020-07-01:
  Tracing service and probes:
    * Added gpu_mem_total ftrace event.
    * Added TrustZone (scm start/end) event.
    * Added protos for GPU memory tracking and updated render stages proto.
    * Added time_in_state probe for Android (CPU time broken down by frequency).

  Trace Processor:
    * Added ingestion of IRQ and SoftIRQ events.
    * Added ingestion of workqueue events. KAddr symbolization still missing.
    * Added ingestion of voltage regulators and board clock change events.
    * Added ingestion of new ION ion_buffer_create/destroy events.
    * Added ingestion of TrustZone (scm start/end) events.
    * Added SurfaceFlinger derived events (tracking of missed frames).
    * Changed parsing of scheduler task state on 4.14 kernels.
    * Changed importing of Java heap graphs: allow partial dumps.
    * Improved performance of the SQL query engine.

  UI:
    * Added dedicated query page for custom SQL queries.
    * Added navigation links for Binder slices.
    * Removed overview summary mode when zoomed out.
    * Fixed recording page when targeting Android P.
    * Improved slice pan/zoom performance by quantizing.