[ltt-dev] LTTng. Strings with missing characters (ash)
Mathieu Desnoyers
compudj at krystal.dyndns.org
Tue Dec 23 13:01:31 EST 2008
OK, I can reproduce the problem :
ash ltt-armall
(or busybox ash ltt-armall) :
Connecting all markers
Connecting fd_state file_descriptor
fs buffer_wait_e
Connecting d
fs buffer_wait_start
fs close
fs exec
fs ioctl
fs llseek
fs lseek
fs ope
Connecting
fs pollfd
fs pread64
fs pwrite64
fs read
fs readv
fs select
fs write
fs writev
global_state statedump_e
Connecting d
i
Connecting put i
Connecting put_eve
Connecting t
ipc call
ipc msg_create
ipc sem_create
....
I'll try to figure out why IFS= behaves differently in ash.
Mathieu
* Mathieu Desnoyers (compudj at krystal.dyndns.org) wrote:
> 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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> > ltt-dev at lists.casi.polymtl.ca
> > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> >
>
> --
> 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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