mark probes : usage examples?

[Wenji Huang]

Om Narasimhan wrote:
> Om Narasimhan wrote:
>> Could anybody point me to some examples for
>>
>> probe kernel.mark("XX")
>>
>> Can't find any in the systemtap examples or tapsets.
>> I would like to know how to identify kernel markers in the kernel 
>> source code as well.
>>
>> Thanks,
>> Om.
> I think I got the answers.
>  From man pages,
> probe kernel.mark("getuid")
> 
> But I can't see any markers in my kernel source (which is pretty new)
> $ pwd
> /space/src/linux-exp
> 
> $ head -n 5 Makefile
> VERSION = 2
> PATCHLEVEL = 6
> SUBLEVEL = 27
> EXTRAVERSION = -rc3
> NAME = Rotary Wombat
> 
> $ findc | xargs grep -En "STAP_MARK"
> $
> 
> findc is my function for find . -iname "*.[ch]"
> 
> Does it mean that we don't have any markers in kernel source so far?

Yes, marker is the facility which can enable users to define static 
probe point in kernel. Users need to insert trace_mark macro into the 
place where they like.

Currently, there is no well-defined marker points in kernel. Maybe 
later, lttng could be merged into mainline. That will provide some 
built-in ones.

Regards,
Wenji