Android Log

This data source is supported only on Android userdebug builds.

The "android.log" data source records log events from the Android log daemon (logd). These are the same log messages that are available via adb logcat.

Both textual events and binary-formatted events from the EventLog are supported.

This allows you to see log events time-synced with the rest of the trace. When recording long traces, it allows you to record event logs indefinitely, regardless of the Android log daemon buffer size (i.e. log events are periodically fetched and copied into the trace buffer).

The data source can be configured to filter event from specific log buffers and keep only the events matching specific tags or priority.

UI

At the UI level, log events are showed in two widgets:

A summary track that allows to quickly glance at the distribution of events and their severity on the timeline.
A table, time-synced with the viewport, that allows to see events within the selected time range.

SQL

select l.ts, t.tid, p.pid, p.name as process, l.prio, l.tag, l.msg
from android_logs as l left join thread as t using(utid) left join process as p using(upid)

ts	tid	pid	process	prio	tag	msg
291474737298264	29128	29128	traced_probes	4	perfetto	probes_producer.cc:231 Ftrace setup (target_buf=1)
291474852699265	625	625	surfaceflinger	3	SurfaceFlinger	Finished setting power mode 1 on display 0
291474853274109	1818	1228	system_server	3	SurfaceControl	Excessive delay in setPowerMode()
291474882474841	1292	1228	system_server	4	DisplayPowerController	Unblocked screen on after 242 ms
291474918246615	1279	1228	system_server	4	am_pss	Pid=28568 UID=10194 Process Name="com.google.android.apps.fitness" Pss=12077056 Uss=10723328 SwapPss=183296 Rss=55021568 StatType=0 ProcState=18 TimeToCollect=51

TraceConfig

Trace proto: AndroidLogPacket

Config proto: AndroidLogConfig

Sample config:

data_sources: {
    config {
        name: "android.log"
        android_log_config {
            min_prio: PRIO_VERBOSE
            filter_tags: "perfetto"
            filter_tags: "my_tag_2"
            log_ids: LID_DEFAULT
            log_ids: LID_RADIO
            log_ids: LID_EVENTS
            log_ids: LID_SYSTEM
            log_ids: LID_CRASH
            log_ids: LID_KERNEL
        }
    }
}