async_track_set_tracker.h | Explore in Territory

/*
 * 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.
 */

#ifndef SRC_TRACE_PROCESSOR_IMPORTERS_COMMON_ASYNC_TRACK_SET_TRACKER_H_
#define SRC_TRACE_PROCESSOR_IMPORTERS_COMMON_ASYNC_TRACK_SET_TRACKER_H_

#include "src/trace_processor/storage/trace_storage.h"

namespace perfetto {
namespace trace_processor {

class TraceProcessorContext;
class AsyncTrackSetTrackerUnittest;

// Tracker used to reduce the number of trace processor tracks corresponding
// to a single "UI track".
//
// UIs using trace processor want to display all slices in the same context
// (e.g. same upid) and same name into a single track. However, because trace
// processor does not allow parallel slices on a single track (because it breaks
// things like span join, self time computation etc.), at the trace processor
// level these parallel slices are put on different tracks.
//
// Creating a new track for every event, however, leads to an explosion of
// tracks which is undesirable. This class exists to multiplex slices so that
// n events correspond to a single track in a way which minimises the number of
// tracks which needs to be merged by the UI.
//
// The intended usage of this class is for callers to first call one of the
// Intern* methods to obtain a TrackSetId followed by Begin/End just before
// calling into SliceTracker's Begin/End respectively. For example:
//  TrackSetId set_id = track_set_tracker->InternProcessTrackSet(upid, name);
//  if (event.begin) {
//    TrackId id = track_set_tracker->Begin(set_id, cookie);
//    slice_tracker->Begin(ts, id, ...)
//  } else {
//    ... (same thing with end)
//  }
// Alternatively, instead of Begin/End, Scoped can also be called if supported
// by the track type.
class AsyncTrackSetTracker { … };

}  // namespace trace_processor
}  // namespace perfetto

#endif  // SRC_TRACE_PROCESSOR_IMPORTERS_COMMON_ASYNC_TRACK_SET_TRACKER_H_
chromium/third_party/perfetto/src/trace_processor/importers/common/async_track_set_tracker.h
