Messages in this thread | | | Date | Sun, 14 Dec 2008 18:52:46 +0100 | From | "Frédéric Weisbecker" <> | Subject | Re: [PATCH] tracing/ftrace: add the printk-msg-only option |
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2008/12/14 Steven Rostedt <rostedt@goodmis.org>: > > On Sat, 13 Dec 2008, Frederic Weisbecker wrote: > >> Impact: display ftrace_printk messages "as is" >> >> By default, ftrace_printk() messages find their output with some other >> informations like pid, caller, ... >> Sometimes a developer just want to have the ftrace_printk left "as is", without >> other information. >> >> This is done by providing a default-off option called printk-msg-only. >> To enable it, just do `echo printk-msg-only > /debugfs/tracing/trace_options` >> >> Before the patch: >> >> <...>-2739 [000] 145.692153: __might_sleep: I'm an ftrace_printk msg in __might_sleep >> <...>-2739 [000] 145.692155: __might_sleep: I'm another ftrace_printk msg in __might_sleep >> >> After the patch and the printk-msg-only option enabled: >> >> I'm an ftrace_printk msg in __might_sleep >> I'm another ftrace_printk msg in __might_sleep >> >> Cc: Steven Rostedt <rostedt@goodmis.org> >> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> >> --- >> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c >> index 8fd3c5a..cd4dbf2 100644 >> --- a/kernel/trace/trace.c >> +++ b/kernel/trace/trace.c >> @@ -287,6 +287,7 @@ static const char *trace_options[] = { >> "annotate", >> "userstacktrace", >> "sym-userobj", >> + "printk-msg-only", > > Hmm, I'm a bit apprehensive about this approach. We are adding a lot of > options that I'm not sure will be used. Is this needed because you added a > ftrace printk that you want to not have the header, or because there are > ftrace printks that exist that you want to turn on and off. Or perhaps, > you want to see the header sometimes and sometimes you do not? > > If it is the later two, then sure we could have this option. But if it is > the former, then we probably should have another type of ftrace_printk > that takes an option to make another event type to tell the output not to > print? > > Oh well, I have patches in mind to clean up the output code anyway. > > -- Steve >
Actually, it's not for my needs but Ingo requested it to have only the message output without the headers while debugging with ftrace_printk.
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