/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

syntax = "proto2";

package perfetto.protos;

// Builtin clock domains used in Perfetto traces.
//
// The default trace time clock is BUILTIN_CLOCK_TRACE_FILE: a synthetic clock
// representing the trace file's own timeline. Each trace file gets its own
// instance (scoped by trace file index).
//
// For backwards compatibility, Perfetto proto traces register BOOTTIME as a
// fallback: if the first timestamp conversion uses a clock other than the
// trace file clock and no explicit clock snapshot data exists, the trace time
// is switched to BOOTTIME. This fallback does not fire for modern traces that
// include ClockSnapshots or that only use the trace file clock directly.
//
// The `primary_trace_clock` field in ClockSnapshot can definitively override
// the trace time clock regardless of the above.
enum BuiltinClock {
  BUILTIN_CLOCK_UNKNOWN = 0;

  // Corresponds to CLOCK_REALTIME. See clock_gettime(2).
  BUILTIN_CLOCK_REALTIME = 1;

  // Corresponds to CLOCK_REALTIME_COARSE. See clock_gettime(2).
  BUILTIN_CLOCK_REALTIME_COARSE = 2;

  // Corresponds to CLOCK_MONOTONIC. See clock_gettime(2).
  BUILTIN_CLOCK_MONOTONIC = 3;

  // Corresponds to CLOCK_MONOTONIC_COARSE. See clock_gettime(2).
  BUILTIN_CLOCK_MONOTONIC_COARSE = 4;

  // Corresponds to CLOCK_MONOTONIC_RAW. See clock_gettime(2).
  BUILTIN_CLOCK_MONOTONIC_RAW = 5;

  // Corresponds to CLOCK_BOOTTIME. See clock_gettime(2).
  // For proto traces, this is used as a backwards-compatible fallback trace
  // time clock when no explicit clock snapshots are present.
  BUILTIN_CLOCK_BOOTTIME = 6;

  // TSC (Time Stamp Counter). Architecture-specific high-resolution counter.
  BUILTIN_CLOCK_TSC = 9;

  // Corresponds to the perf event clock (PERF_CLOCK).
  BUILTIN_CLOCK_PERF = 10;

  // A synthetic clock representing the trace file's own timeline. Each trace
  // file gets its own instance (scoped by trace file index). This is the
  // default trace time clock before any clock snapshot or format-specific
  // override takes effect.
  BUILTIN_CLOCK_TRACE_FILE = 11;

  BUILTIN_CLOCK_MAX_ID = 63;

  reserved 7, 8;
}
