Re: [PATCH] doc: clarify that trace_events= takes a comma-separated list

From: Brian Norris
Date: Mon May 23 2016 - 16:32:52 EST


On Mon, May 23, 2016 at 04:25:44PM -0400, Steven Rostedt wrote:
> On Mon, 23 May 2016 13:08:31 -0700
> Brian Norris <computersforpeace@xxxxxxxxx> wrote:
>
> > It took me browsing through the source code to determine that I was,
> > indeed, using the wrong delimiter in my command lines. So I might as
> > well document it for the next person.
> >
> > Signed-off-by: Brian Norris <computersforpeace@xxxxxxxxx>
> > ---
> > Documentation/kernel-parameters.txt | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > index 5349363b603c..594bf50b8f81 100644
> > --- a/Documentation/kernel-parameters.txt
> > +++ b/Documentation/kernel-parameters.txt
> > @@ -3994,7 +3994,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> >
> > trace_event=[event-list]
> > [FTRACE] Set and start specified trace events in order
> > - to facilitate early boot debugging.
> > + to facilitate early boot debugging. The event-list is a
> > + comma separated list of trace events to enable, as if
> > + you were to append the event(s) to
> > +
> > + /sys/kernel/debug/tracing/set_event
> > +
>
> I agree that we should document that the list is comma separated, but
> the wording you have above, makes it sound like the set_event file
> also takes a comma separated list, which it does not. That file
> requires a space separated list.

Hmm, good point. I added the latter half of the sentence at the last
moment, so I didn't give that part as good of a read.

> Can you reword that so that it removes the confusion. Thanks!

Sure, I'll try. Would it be OK if I just dropped the latter part of the
sentence, and didn't mention /sys/.../set_event at all? Like:

"The event-list is a comma separated list of trace events to enable.
See also Documentation/trace/events.txt"

Brian