Is it possible to read the Slog in android monitor?

Question

In the android source code i see often line like Slog.v(WindowManagerService.TAG, "First window added to " + this + ", creating SurfaceSession"); How can i see those Slog under android monitor ? And what the difference between Slog and Log?

Answer 1

Short answer

You get logs logged with Slog by default, but they are "hidden" between other log messages. In order to get just the ones logged with Slog use this command:

adb logcat -b system

Long answer

I looked at source of Slog.java:

public static int v(String tag, String msg) {
    return Log.println_native(Log.LOG_ID_SYSTEM, Log.VERBOSE, tag, msg);
}

Compared to Log.java:

public static int v(String tag, String msg) {
    return println_native(LOG_ID_MAIN, VERBOSE, tag, msg);
}

As you can see, the difference is solely in LOG_ID parameter.

Then I looked at adb logcat -help:

  ...
  -b <buffer>     Request alternate ring buffer, 'main', 'system', 'radio',
                  'events', 'crash' or 'all'. Multiple -b parameters are
                  allowed and results are interleaved. The default is
                  -b main -b system -b crash.
  ...

I did not check any further - it looks like a safe bet that -b option corresponds to different LOG_ID params.