Re: [PATCH] trace-cmd: Suppress trace library warnings

[Tzvetomir Stoyanov <tz.stoyanov@gmail.com>]

On Thu, Apr 15, 2021 at 4:34 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 15 Apr 2021 11:03:16 +0300
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > Suppress all warnings from libtraceevent, libtracefs and libtracecmd if
> > the trace-cmd application does not run in debug mode.
>
> Actually, don't we have a -q option to turn off warnings from trace-cmd?
>
> From the man page:
>
>        -q
>            Quiet non critical warnings.
>
> Which I see, currently doesn't work, but should. Not being able to parse
> events is something we should keep displaying by default, but it should
> not be displayed if -q is on the command line.
>

I can fix "-q" to suppress warnings from all trace libraries, but the
problem is that "-q" is not set by default. These "Not being able to
parse" messages could be very annoying in some cases and as I
understood they are not critical ? The other problem is that not all
trace-cmd commands have the "-q" option, but almost all of them need a
tep handler that could cause printing of these messages.
Yodan found one more issue, the pr_stat() libtraceevent function is
not affected by tep_vwarning() redefine. It prints statistics on
KernelShark startup. I think we should add some kind of priorities of
all those library messages and decide which of them when will be
printed.  It makes sense only for fatal library messages to be printed
by default, if the "-q" option is not set. All others should be
visible only if trace-cmd runs in debug mode.

> -- Steve
>
[...]


--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center