From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: rostedt <rostedt@goodmis.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
fweisbec <fweisbec@gmail.com>, Jessica Yu <jeyu@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>, chris <chris@chris-wilson.co.uk>,
yuanhan liu <yuanhan.liu@linux.intel.com>,
Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Subject: Re: [PATCH][RFC] tracing: Enable tracepoints via module parameters
Date: Tue, 20 Apr 2021 11:15:10 -0400 (EDT) [thread overview]
Message-ID: <1672102317.2266.1618931710794.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20210420105511.65490e8d@gandalf.local.home>
----- On Apr 20, 2021, at 10:55 AM, rostedt rostedt@goodmis.org wrote:
> On Tue, 20 Apr 2021 09:29:27 -0400 (EDT)
> Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:
>
>> ----- On Apr 20, 2021, at 8:55 AM, rostedt rostedt@goodmis.org wrote:
>> [...]
>> >
>> > Would adding automatic module parameters be an issue? That is, you can add
>> > in the insmod command line a parameter that will enable tracepoints. We
>> > could have a way to even see them from the modinfo. I think I had that
>> > working once, and it wasn't really that hard to do.
>>
>> There is one thing we should consider here in terms of namespacing: those module
>> command line parameters should be specific to each tracer (e.g. ftrace, perf,
>> ebpf).
>>
>> LTTng for instance already tackles early module load tracing in a different
>> way: users can enable instrumentation of yet-to-be loaded kernel modules. So
>> it would not make sense in that scheme to have module load parameters.
>>
>> It's a different trade-off in terms of error reporting though: for instance,
>> LTTng won't report an error if a user does a typo when entering an event name.
>>
>> So I think those command line parameters should be tracer-specific, do you agree
>> ?
>
>
> No, I do not agree. I would like to make it consistent with the kernel
> command line. As you can put in: "trace_event=sched_switch" and the
> sched_switch trace point will be enable (for the tracefs directory) on boot
> up. The same should be for modules as well.
>
> It shouldn't affect LTTng, as you already have a way to enable them as they
> get loaded.
That sounds fine. So that would be within the "trace_event" (and not tracepoint)
namespace for module load parameters as well ?
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2021-04-20 15:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-08 22:18 [PATCH][RFC] tracing: Enable tracepoints via module parameters Steven Rostedt
2011-03-08 22:42 ` Steven Rostedt
2011-03-08 23:22 ` Mathieu Desnoyers
2011-03-08 23:32 ` Steven Rostedt
2011-03-09 0:07 ` Mathieu Desnoyers
2011-03-09 0:14 ` Steven Rostedt
2011-03-09 0:29 ` Mathieu Desnoyers
2011-03-09 0:52 ` Steven Rostedt
2011-03-09 1:17 ` Mathieu Desnoyers
2011-03-09 2:01 ` Steven Rostedt
2011-03-09 2:30 ` Mathieu Desnoyers
2011-03-09 2:01 ` Yuanhan Liu
2011-03-09 2:12 ` Steven Rostedt
2011-03-09 2:19 ` Yuanhan Liu
2011-03-10 23:33 ` Rusty Russell
2013-08-13 15:14 ` Steven Rostedt
2013-08-13 22:34 ` Mathieu Desnoyers
2013-08-13 23:09 ` Steven Rostedt
2013-08-15 2:02 ` Rusty Russell
2013-08-15 3:32 ` Steven Rostedt
2021-04-19 21:54 ` Williams, Dan J
2021-04-19 22:11 ` Steven Rostedt
2021-04-20 1:25 ` Dan Williams
2021-04-20 12:55 ` Steven Rostedt
2021-04-20 13:29 ` Mathieu Desnoyers
2021-04-20 14:55 ` Steven Rostedt
2021-04-20 15:15 ` Mathieu Desnoyers [this message]
2021-04-20 15:34 ` Steven Rostedt
2021-04-20 19:54 ` Dan Williams
2021-04-20 20:32 ` Steven Rostedt
2021-04-21 6:27 ` Dan Williams
2021-04-21 7:30 ` Rasmus Villemoes
2021-04-21 14:20 ` Steven Rostedt
2021-04-21 14:50 ` Rasmus Villemoes
2021-04-21 15:00 ` Steven Rostedt
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