[ltt-dev] LTTng. Strings with missing characters (ARM)
Mathieu Desnoyers
compudj at krystal.dyndns.org
Tue Dec 23 12:47:26 EST 2008
And also, what type of shell are you using (type, version) ?
Mathieu
* Mathieu Desnoyers (mathieu.desnoyers at polymtl.ca) wrote:
> (adding the ltt-dev list in CC, so other developers can have a look at
> it and help reproducing this ARM problem)
>
> Hrm, weird,
>
> So /proc/ltt outputs correct strings, but ltt-armall output is messed
> up.
>
> Can you do the following ?
>
> which ltt-armall
>
> and
>
> cat `which ltt-armall`
>
> I guess it has something to do with the IFS=$'\n' line in the script,
> which works on x86, but maybe not on arm for some reason.
>
> Also, can you give me the output after this sequence of commands ?
> ltt-armall
> lttctl -C -w /tmp/trace trace
> find /mnt/debugfs/ltt (where /mnt/debugfs is the path to your debugfs
> mount)
>
> Thanks
>
> Mathieu
>
> * Akyurek, Ali (EXT) (ali.akyurek.ext at siemens.com) wrote:
> >
> > Hello,
> >
> > Strings are seem to be cutted off at 'n' character.
> >
> > -----Ursprüngliche Nachricht-----
> > Von: Mathieu Desnoyers [mailto:mathieu.desnoyers at polymtl.ca]
> > Gesendet: Montag, 22. Dezember 2008 19:51
> > An: Akyurek, Ali (EXT)
> > Betreff: Re: LTTng. Strings with missing characters
> >
> >
> > Hrm,
> >
> > What do you get if you do :
> >
> > cat /proc/ltt ?
> >
> > And what is your kernel config ?
> >
> > Mathieu
> >
> > * Akyurek, Ali (EXT) (ali.akyurek.ext at siemens.com) wrote:
> > >
> > >
> > >
> > > Hello again,
> > >
> > > I've installed latest versions LTTng 0.70, lttcontrol 0.61.
> > >
> > > When i run armall, in the output, i see strings with missing characters like:
> > >
> > > ...
> > > Connecting el irq_exit
> > > ker
> > > Connecting el kthread_create
> > > ker
> > > Connecting el kthread_stop
> > > ker
> > > Connecting el kthread_stop_ret
> > > ker
> > > ...
> > >
> > >
> > > Also after i'm done with tracing, the trace output directory looks like:
> > >
> > > drwxr-xr-x 2 root 0 0 Jan 1 02:12 .
> > > drwxr-xr-x 3 root 0 0 Jan 1 01:55 ..
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 _page_e_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 d_sig_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 dle_fault_e_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 el_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 etif_state_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 etwork_ip_i_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 etwork_ipv4_i_0
> > > -rwxr-xr-x 1 root 0 65536 Jan 1 01:55 fd_state_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 metadata_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 mm_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 put_0
> > > -rwxr-xr-x 1 root 0 262144 Jan 1 01:55 put_eve_0
> > >
> > > Do you have an idea about it?
> > >
> > > Thanks.
> > >
> > >
> > > -----Ursprüngliche Nachricht-----
> > > Von: Mathieu Desnoyers [mailto:mathieu.desnoyers at polymtl.ca]
> > > Gesendet: Freitag, 19. Dezember 2008 18:17
> > > An: Akyurek, Ali (EXT)
> > > Betreff: Re: arm userspace tracing
> > >
> > > Hello !
> > >
> > > Well, it's your lucky day I guess. I just added a neat feature to LTTng
> > > which will help a great deal sending a subset of the data types
> > > supported (a simple string) into the trace buffers from userspace _very_
> > > easily. It's not integrated with the event management, so I would not
> > > add this to application in production (because it would add overhead
> > > even when tracing is disabled). With the latest LTTng, all you have to
> > > do is :
> > >
> > > modprobe ltt-userspace-event
> > > lttctl -C -w /tmp/trace trace (note : the arguments recently changed)
> > > run stuff...
> > > echo "Some event happened!" > /mnt/debugfs/ltt/write_event
> > > lttctl -D trace
> > > looking specifically for the event :
> > > lttv -e userspace.event -m textDump -t /tmp/trace
> > >
> > > So basically, you can look for your own string into the trace stream as
> > > a starting point. This is portable, so should work on ARM without any
> > > problem.
> > >
> > > There is still a lot of work to do on ARM to have per-site activation of
> > > tracepoints like we currently have in the kernel, but at least this
> > > solution gives us _something_. It's just that it's always enabled.
> > >
> > > * Akyurek, Ali (EXT) (ali.akyurek.ext at siemens.com) wrote:
> > > > Hello Mr.Desnoyers,
> > > >
> > > > First of all, thanks for the great work you've done.
> > > > What i wonder is that is it possible to trace user space in arm architecture?
> > > > In the quick start document it writes :
> > > >
> > > > "Get the latest markers-userspace-*.tar.bz2 and see the Makefile and examples. It
> > > > allows inserting markers in executables and libraries, currently only on x86_32
> > > > and x86_64."
> > > >
> > > > But ,then i've seen a patch in http://ltt.polymtl.ca/packages/markers-user/ called lttng-userspace-tracing-arm.patch <http://ltt.polymtl.ca/packages/markers-user/lttng-userspace-tracing-arm.patch> .
> > > >
> > >
> > > That was a complete syscall implementation at some point, which could be
> > > ported to the new infrastructure, but note that the current
> > > markers-userspace-*.tar.bz2 code also needs linker script modification.
> > >
> > > Mathieu
> > >
> > > > Thanks.
> > > >
> > > > Mit freundlichem Gruss / Best Regards
> > > > Ali Günhan Akyürek
> > > > evoline TR
> > > >
> > >
> > > --
> > > Mathieu Desnoyers
> > > OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
> > >
> >
> > --
> > Mathieu Desnoyers
> > OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
> >
>
> --
> Mathieu Desnoyers
> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
>
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--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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