android13/external/perfetto/docs/data-sources/system-log.md

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## Syscalls
The enter and exit of all syscalls can be tracked in Perfetto traces.
The following ftrace events need to added to the trace config to collect syscalls.
```protobuf
data_sources: {
config {
name: "linux.ftrace"
ftrace_config {
ftrace_events: "raw_syscalls/sys_enter"
ftrace_events: "raw_syscalls/sys_exit"
}
}
}
```
## Linux kernel tracing
Perfetto integrates with [Linux kernel event tracing](https://www.kernel.org/doc/Documentation/trace/ftrace.txt).
While Perfetto has special support for some events (for example see [CPU Scheduling](#cpu-scheduling)) Perfetto can collect arbitrary events.
This config collects four Linux kernel events:
```protobuf
data_sources {
config {
name: "linux.ftrace"
ftrace_config {
ftrace_events: "ftrace/print"
ftrace_events: "sched/sched_switch"
ftrace_events: "task/task_newtask"
ftrace_events: "task/task_rename"
}
}
}
```
The full configuration options for ftrace can be seen in [ftrace_config.proto](/protos/perfetto/config/ftrace/ftrace_config.proto).
## Android system logs
### Android logcat
Include Android Logcat messages in the trace and view them in conjunction with other trace data.
![](/docs/images/android_logs.png)
You can configure which log buffers are included in the trace. If no buffers are specified, all will be included.
```protobuf
data_sources: {
config {
name: "android.log"
android_log_config {
log_ids: LID_DEFAULT
log_ids: LID_SYSTEM
log_ids: LID_CRASH
}
}
}
```
You may also want to add filtering on a tags using the `filter_tags` parameter or set a min priority to be included in the trace using `min_prio`.
For details about configuration options, see [android\_log\_config.proto](/protos/perfetto/config/android/android_log_config.proto).
The logs can be investigated along with other information in the trace using the [Perfetto UI](https://ui.perfetto.dev) as shown in the screenshot above.
If using the `trace_processor`, these logs will be in the [android\_logs](/docs/analysis/sql-tables.autogen#android_logs) table. To look at the logs with the tag perfetto you would use the following query:
```sql
select * from android_logs where tag = "perfetto" order by ts
```
### Android application tracing
You can enable atrace through Perfetto.
![](/docs/images/userspace.png)
Add required categories to `atrace_categories` and set `atrace_apps` to a specific app to collect userspace annotations from that app.
```protobuf
data_sources: {
config {
name: "linux.ftrace"
ftrace_config {
atrace_categories: "view"
atrace_categories: "webview"
atrace_categories: "wm"
atrace_categories: "am"
atrace_categories: "sm"
atrace_apps: "com.android.phone"
}
}
}
```