[ltt-dev] net extended trace openin error with LTTV (without attachment)

Mathieu Desnoyers compudj at krystal.dyndns.org
Mon Feb 8 10:36:34 EST 2010


* paljak at mit.bme.hu (paljak at mit.bme.hu) wrote:
> Hi Ben,
> 
> I have been working with LTTng lately and the more I know it, the more I 
> like it! 
> 
> I've also been able to open and examine traces, and it looks very 
> interesting. 
> 
> I've also tried to create my own, but I've ran into an error, could you 
> take a look?
> 
> Basically, I receive an error 
> (ERROR:tracefile.c:1582:ltt_update_event_size: assertion failed: (info != 
> NULL)) every time i try to open a net_extended trace with LTTV.
> 
> Here's what i've done:
> 
> 1. Downloaded the patched kernel: git clone 
> git://git.kernel.org/pub/scm/linux/kernel/git/compudj/linux-2.6-lttng.git
> 2. Compiled the kernel with these options (.config):
> #
> # GCOV-based kernel profiling
> #
> # CONFIG_GCOV_KERNEL is not set
> CONFIG_SLOW_WORK=y
> # CONFIG_SLOW_WORK_DEBUG is not set
> CONFIG_LTT=y
> CONFIG_LTT_FILTER=m
> CONFIG_HAVE_LTT_DUMP_TABLES=y
> CONFIG_LTT_RELAY=y
> CONFIG_LTT_RELAY_LOCKLESS=y
> # CONFIG_LTT_RELAY_IRQOFF is not set
> # CONFIG_LTT_RELAY_LOCKED is not set
> CONFIG_LTT_SERIALIZE=y
> CONFIG_LTT_FAST_SERIALIZE=y
> CONFIG_LTT_TRACEPROBES=m
> CONFIG_LTT_TRACE_CONTROL=y
> CONFIG_LTT_TRACER=y
> CONFIG_LTT_ALIGNMENT=y
> CONFIG_LTT_CHECK_ARCH_EFFICIENT_UNALIGNED_ACCESS=y
> # CONFIG_LTT_DEBUG_EVENT_SIZE is not set
> CONFIG_LTT_USERSPACE_EVENT=m
> CONFIG_LTT_VMCORE=y
> CONFIG_LTT_STATEDUMP=m
> CONFIG_LTT_KPROBES=m
> # CONFIG_LTT_ASCII is not set
> 3. Install the kernel and boot it up
> 4. Load all the modules
> modprobe -v ltt-trace-control
> modprobe -v ltt-marker-control
> modprobe -v ltt-tracer
> modprobe -v ltt-serialize
> modprobe -v ltt-relay
> modprobe -v ipc-trace
> modprobe -v kernel-trace
> modprobe -v mm-trace
> modprobe -v net-trace
> modprobe -v fs-trace
> modprobe -v jbd2-trace
> modprobe -v ext4-trace
> modprobe -v syscall-trace
> modprobe -v trap-trace
> modprobe -v ltt-statedump
> #extended trace
> modprobe -v net-extended-trace
> 5. ltt-armall -n
> 6. lttctl -C -w /tmp/tr1 tr1
> 7. wget http://google.com
> 8. lttctl -D tr1
> 9. lttv -m textDump -t tr1
> **
> ERROR:tracefile.c:1582:ltt_update_event_size: assertion failed: (info != 
> NULL)
> /usr/local/bin/lttv: line 15:  2083 Aborted                 $0.real $*
> 10. lttv -m textDump -t tr1 --verbose --debug --edebug
> net.udpv4_rcv_extended: 1003.743082325 (/tmp/tr1/net_0), 1878, 1878, 
> gnome-terminal, , 1, 0x0, SOFTIRQ { skb = 0xC4BBC240, saddr = 3576624693, 
> daddr = 3232235780, unicast = 1, ulen = 110, source = 53, dest = 39087, 
> data_start = a299884901000100 }
> Event header (tracefile /tmp/tr1/net_0 offset bb8):
>      bb8    40 C2 BB C4 
> **
> ERROR:tracefile.c:1582:ltt_update_event_size: assertion failed: (info != 
> NULL)
> /usr/local/bin/lttv: line 15:  2104 Aborted                 $0.real $*
> 
> The installed versions are:
> Linux Trace Toolkit Visualizer 0.12.29-02022010
> Linux Trace Toolkit Trace Control 0.79-01022010
> 
> Here's the created trace for reference: 
> http://www.mit.bme.hu/~paljak/trace.tgz
> 
> If I don't use net extended, than it works just fine. And I've also had 
> success open your example trace.
> 
> Do you have any idea why do I get this error and how could I correct it?

That looks like a field type error in the net extended event. Can you
tell us what LTTng version you use ? (git branch should tell you)

Is your traced machine 32 or 64 bits ? And what about the machine
running lttv ?

Reviewing ltt/probes/net-extended-trace.c might help.

Thanks,

Mathieu

> 
> Thank you in advance!
> 
> Cheers,
> Gergely
> 
> p.s. Sorry for the large attachment in the previous mail, now I've 
> replaced it with a link.
> 
> 
> 
> From:
> Benjamin Poirier <benjamin.poirier at polymtl.ca>
> To:
> paljak at mit.bme.hu
> Cc:
> ltt-dev at lists.casi.polymtl.ca
> Date:
> 2010.02.03 21:09
> Subject:
> Re: LTTng net_extended_trace - example data
> 
> 
> 
> Hello Gergely,
> 
> You can find a set of traces, results57, which work with the newest lttv 
> at
> http://lttng.org/~ben/results57.tar.bz2
> 
> These work with lttv 0.12.29
> http://lttng.org/files/packages/lttv-0.12.29-02022010.tar.gz
> and with the current git head.
> 
> Compile and install lttv from the tar archive, then run:
> lttv-gui --sync --sync-stats -t results57/node1 -t results57/node2
> If you are confortable building from git, you can compile and then run:
> ./runlttv -a"--sync --sync-stats" results57/node*
> 
> These traces showcase two programs: "broadcaster" which is a traffic
> generator and an ssh session, which is more interesting.
> 
> Have a look around time 3092s, pid 1896 on node2 is the ssh client and
> pid 1927 on node1 is the sshd server. The two are running on different
> machines but the traces align accurately. In this case, the average
> accuracy is +/- 28us. You can compare this without synchronization:
> rerun lttv without the --sync options. The client and server are miles
> appart.
> 
> If you'd like to try out advanced synchronization options, have a look
> at lttv/lttv/sync/README. If you encounter problems or have further
> questions, you are welcome to contact me or the ltt-dev mailing list 
> again.
> 
> -Ben
> 
> paljak at mit.bme.hu wrote:
> > Dear Benjamin,
> >
> > I am writing about your net_extended_trace extension to LTTng, I am
> > evaluating it for a project. I looked up your e-mail announcing it on
> > the lttng-dev mailing list, and I wanted to download the sample data
> > from here: http://hal.drap.polymtl.ca/results55.tar.bz2 , but it is no
> > longer available.
> >
> > Could you send it by e-mail or make it available somewhere online? I'd
> > like to check out a sample before digging too deep into LTTng if it
> > fits the needs of the project.
> >
> > Thank you very much in advance!
> >
> > Yours sincerely,
> > Gergely
> >
> > -- 
> > Gergely Paljak
> > PhD Student
> > Budapest University of Technology and Economics 
> 
> 
> 

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> ltt-dev at lists.casi.polymtl.ca
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-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68




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