linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Steven Rostedt <rostedt@goodmis.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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-wilson.co.uk,
	yuanhan liu <yuanhan.liu@linux.intel.com>,
	"Grumbach, Emmanuel" <emmanuel.grumbach@intel.com>
Subject: Re: [PATCH][RFC] tracing: Enable tracepoints via module parameters
Date: Tue, 20 Apr 2021 10:55:11 -0400	[thread overview]
Message-ID: <20210420105511.65490e8d@gandalf.local.home> (raw)
In-Reply-To: <1154727029.2004.1618925367044.JavaMail.zimbra@efficios.com>

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.

-- Steve

  reply	other threads:[~2021-04-20 14:55 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 [this message]
2021-04-20 15:15                     ` Mathieu Desnoyers
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210420105511.65490e8d@gandalf.local.home \
    --to=rostedt@goodmis.org \
    --cc=chris@chris-wilson.co.uk \
    --cc=dan.j.williams@intel.com \
    --cc=emmanuel.grumbach@intel.com \
    --cc=fweisbec@gmail.com \
    --cc=jeyu@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=mingo@elte.hu \
    --cc=yuanhan.liu@linux.intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).