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SubjectRe: about use wild cards for set_ftrace_filter and so on

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.

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.


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