From: Tom Zanussi <zanussi@kernel.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: rostedt@goodmis.org, tglx@linutronix.de, namhyung@kernel.org,
vedang.patel@intel.com, bigeasy@linutronix.de,
joel@joelfernandes.org, mathieu.desnoyers@efficios.com,
julia@ni.com, linux-kernel@vger.kernel.org,
linux-rt-users@vger.kernel.org
Subject: Re: [PATCH v4 8/8] trace: Add alternative synthetic event trace action syntax
Date: Tue, 18 Sep 2018 14:16:43 -0500 [thread overview]
Message-ID: <1537298203.11628.8.camel@kernel.org> (raw)
In-Reply-To: <20180919035446.4fb6b856ab51229984eb2736@kernel.org>
Hi Masami,
On Wed, 2018-09-19 at 03:54 +0900, Masami Hiramatsu wrote:
> Hi Tom,
>
> On Mon, 10 Sep 2018 14:10:46 -0500
> Tom Zanussi <zanussi@kernel.org> wrote:
>
> > From: Tom Zanussi <tom.zanussi@linux.intel.com>
> >
> > Add a 'trace(synthetic_event_name, params)' alternative to
> > synthetic_event_name(params).
> >
> > Currently, the syntax used for generating synthetic events is to
> > invoke synthetic_event_name(params) i.e. use the synthetic event
> > name
> > as a function call.
> >
> > Users requested a new form that more explicitly shows that the
> > synthetic event is in effect being traced. In this version, a new
> > 'trace()' keyword is used, and the synthetic event name is passed
> > in
> > as the first argument.
>
> Hmm, what is the advantage of adding this new form?
>
There's no real advantage other than user preference - Namhyung thought
that since the event-name-as-function-call actions are all defined as
ACTION_TRACE, there should also be an explicit 'trace' action.
So I added it as alternative syntax - the event-name-as-function-call
form remains unchanged.
By the way, I also have a patch implementing your alternative syntax
change, where if you have only one handler, you can do away with the
explicit action.handler form e.g.
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-ts0: \
onmax($wakeup_lat): \
save(next_prio,next_comm,prev_pid,prev_prio,prev_comm):snapshot() \
if next_comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
It just wasn't ready to go in with the v4 patches yet, so I decided
to submit it later as a follow-on.
Tom
> Thanks,
>
next prev parent reply other threads:[~2018-09-18 19:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-10 19:10 [PATCH v4 0/8] tracing: Hist trigger snapshot and onchange additions Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 1/8] tracing: Refactor hist trigger action code Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 2/8] tracing: Split up onmatch action data Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 3/8] tracing: Generalize hist trigger onmax and save action Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 4/8] tracing: Add conditional snapshot Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 5/8] tracing: Move hist trigger key printing into a separate function Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 6/8] tracing: Add snapshot action Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 7/8] tracing: Add hist trigger onchange() handler Tom Zanussi
2018-09-10 19:10 ` [PATCH v4 8/8] trace: Add alternative synthetic event trace action syntax Tom Zanussi
2018-09-18 18:54 ` Masami Hiramatsu
2018-09-18 19:16 ` Tom Zanussi [this message]
2018-09-18 23:54 ` Masami Hiramatsu
2018-09-19 16:33 ` Tom Zanussi
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