Messages in this thread | | | Date | Thu, 27 Nov 2008 16:58:06 +0100 | From | "Frédéric Weisbecker" <> | Subject | Re: about use wild cards for set_ftrace_filter and so on |
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2008/11/27 walimis <walimisdev@gmail.com>: > On Thu, Nov 27, 2008 at 10:34:19AM -0500, Steven Rostedt wrote: >> >>On Thu, 27 Nov 2008, walimis wrote: >> >>> >>> I encountered an issue when using ftrace. >>> We know that we can use wild cards to set set_ftrace_filter, but there's >>> problem when using such as "echo h* > /debug/tracing/set_ftrace_filter". >>> If there are files named with "h" prefix in current directory, echo "h*" >>> will echo these files' name to set_ftrace_filter, not "h*". >>> For example: >>> >>> #cat /debug/tracing/available_filter_functions |grep ^hr |wc -l >>> 23 >>> #ls >>> #touch hraa hrdd >>> #ls >>> hraa hrdd >>> #echo hr* > /debug/tracing/set_ftrace_filter >>> #cat /debug/tracing/set_ftrace_filter >>> >>> No output in /debug/tracing/set_ftrace_filter! >>> If we use "" to enclose wild cards, it works: >>> >>> #ls >>> hraa hrdd >>> #echo "hr*" > /debug/tracing/set_ftrace_filter >>> #cat /debug/tracing/set_ftrace_filter |wc -l >>> 23 >>> >>> This problem can lead to unexpected result if current directory has a >>> lot of files. >>> I suppose that we can add some notes to document, so a patch attached. >> >>Using TB? It's best to inline the patch, that way I can comment on it >>better. > Using mutt, but I don't know how to inline the patch now. > >> >>Anyway, you should fix the example. I also recommend a single quote over >>double, to prevent any other translation that bash might do. >> >>The example in ftrace.txt should be: >> >> # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter >> >> >>Thanks, >> >>-- Steve >> >>/me goes back to eating turkeys. > I only add a note, but I wonder whether enough. > If needed, I can add a example to this document. > > Impact: imporve document > > Signed-off-by: walimis <walimisdev@gmail.com> > --- > Documentation/ftrace.txt | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt > index de05042..9735434 100644 > --- a/Documentation/ftrace.txt > +++ b/Documentation/ftrace.txt > @@ -1251,6 +1251,9 @@ These are the only wild cards which are supported. > > <match>*<match> will not work. > > +Note: you'd better to use '' to enclose wild cards, otherwise in some > +case you can't get the correct result. > + > # echo hrtimer_* > /debug/tracing/set_ftrace_filter > > Produces: > -- > 1.6.0.3
Cc'ed Ingo.
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