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 <20230801114545.GD79828@hirez.programming.kicks-ass.net>
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From:   Ze Gao <zegao2021@gmail.com>
Date:   Tue, 1 Aug 2023 21:08:54 +0800
Message-ID: <CAD8CoPBb7-j7RLggWfu+Y-bmb_VW_0O46MyH35vWL=24C3Tndw@mail.gmail.com>
Subject: Re: [RFC PATCH v3 3/6] sched, tracing: add to report task state in
 symbolic chars
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Adrian Hunter <adrian.hunter@intel.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org,
        linux-trace-devel@vger.kernel.org, Ze Gao <zegao@tencent.com>
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Sorry that I don't get this one, did you mean kernel subsystems like
bpf or third party modules?  Honestly I don't know how it works here
for userspace to consume the raw tracepoint without looking at
tracefs.

Regards,
Ze

On Tue, Aug 1, 2023 at 7:46=E2=80=AFPM Peter Zijlstra <peterz@infradead.org=
> wrote:
>
> On Tue, Aug 01, 2023 at 05:01:21PM +0800, Ze Gao wrote:
> > @@ -233,6 +255,7 @@ TRACE_EVENT(sched_switch,
> >               __field(        pid_t,  prev_pid                        )
> >               __field(        int,    prev_prio                       )
> >               __field(        long,   prev_state                      )
> > +             __field(        char,   prev_state_char                 )
> >               __array(        char,   next_comm,      TASK_COMM_LEN   )
> >               __field(        pid_t,  next_pid                        )
> >               __field(        int,    next_prio                       )
>
> And this again will wreck everybody that consumes the raw tracepoint
> without looking at tracefs.