UI: ETM: session track for etm (#2712)

Adds a track to the UI that plots the current ETM session number on the
timeline.

Author: OmarElfouly

src/trace_processor/importers/etm/etm_v4_stream.cc

@@ -26,6 +26,10 @@
 #include "perfetto/ext/base/status_macros.h"
 #include "perfetto/trace_processor/trace_blob.h"
 #include "perfetto/trace_processor/trace_blob_view.h"
+#include "src/trace_processor/importers/common/event_tracker.h"
+#include "src/trace_processor/importers/common/track_tracker.h"
+#include "src/trace_processor/importers/common/tracks.h"
+#include "src/trace_processor/importers/common/tracks_common.h"
 #include "src/trace_processor/importers/etm/etm_v4_stream_demultiplexer.h"
 #include "src/trace_processor/importers/etm/frame_decoder.h"
 #include "src/trace_processor/importers/etm/opencsd.h"
@@ -139,9 +143,21 @@ base::Status EtmV4Stream::OnItraceStartRecord(
 void EtmV4Stream::StartSession(std::optional<int64_t> start_ts) {
   PERFETTO_CHECK(stream_active_);
   PERFETTO_CHECK(!session_.has_value());
-  session_.emplace(context_->storage->mutable_etm_v4_session_table()
-                       ->Insert({config_id_, start_ts})
-                       .id);
+  auto session_id = context_->storage->mutable_etm_v4_session_table()
+                        ->Insert({config_id_, start_ts})
+                        .id;
+  session_.emplace(session_id);
+
+  if (start_ts) {
+    static constexpr auto kETMSessionBlueprint =
+        tracks::CounterBlueprint("etm_session", tracks::UnknownUnitBlueprint(),
+                                 tracks::DimensionBlueprints(),
+                                 tracks::StaticNameBlueprint("ETMSession"));
+    TrackId track_id =
+        context_->track_tracker->InternTrack(kETMSessionBlueprint);
+    context_->event_tracker->PushCounter(
+        start_ts.value(), static_cast<double>(session_id.value), track_id);
+  }
 }
 
 void EtmV4Stream::AddChunk(TraceBlobView chunk) {

ui/src/plugins/org.chromium.ETM/OWNERS

@@ -0,0 +1,2 @@
+[email protected]
+[email protected]

ui/src/plugins/org.chromium.ETM/index.ts

@@ -0,0 +1,55 @@
+// Copyright (C) 2025 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.
+
+import {Trace} from '../../public/trace';
+import {PerfettoPlugin} from '../../public/plugin';
+
+import {createQueryCounterTrack} from '../../components/tracks/query_counter_track';
+import {TrackNode} from '../../public/workspace';
+
+export default class implements PerfettoPlugin {
+  static readonly id = 'org.chromium.ETM';
+
+  async onTraceLoad(trace: Trace) {
+    const title = 'ETM Session ID';
+    const uri = `${trace.pluginId}#ETMSessionID`;
+    const query =
+      'select ts, value from counter inner join ' +
+      'counter_track on counter_track.id = counter.track_id ' +
+      'where name = "ETMSession"';
+
+    const renderer = await createQueryCounterTrack({
+      trace,
+      uri,
+      data: {
+        sqlSource: query,
+      },
+    });
+
+    trace.tracks.registerTrack({
+      uri,
+      renderer,
+      description: 'Track to show current ETM session on timeline',
+    });
+
+    const group = new TrackNode({
+      name: 'ETM',
+      isSummary: true,
+    });
+
+    const trackNode = new TrackNode({uri, name: title});
+    group.addChildInOrder(trackNode);
+    trace.workspace.addChildInOrder(group);
+  }
+}