[ltt-dev] no channel available - IBM BlueGene cluster

[Alessandro Morari]

Yes I installed statically all the modules. Btw I have also applied
some patches relative to this specific architecture (Blue Gene), but there
are not conflicts with
the lttng patch. This is my .config for LTTng:

$grep LTT .config
CONFIG_LTT=y
CONFIG_LTT_FILTER=y
# CONFIG_HAVE_LTT_DUMP_TABLES is not set
CONFIG_LTT_RELAY_ALLOC=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=y
CONFIG_LTT_TRACE_CONTROL=y
CONFIG_LTT_TRACER=y
 CONFIG_LTT_ALIGNMENT is not set
CONFIG_LTT_CHECK_ARCH_EFFICIENT_UNALIGNED_ACCESS=y
# CONFIG_LTT_DEBUG_EVENT_SIZE is not set
CONFIG_LTT_USERSPACE_EVENT=y
CONFIG_LTT_VMCORE=y
CONFIG_LTT_KPROBES=y
CONFIG_LTT_STATEDUMP=y
# CONFIG_LTT_ASCII is not set

Also grep LTT dmesg give this:
[   20.491154]:0 LTT : ltt-relay init
[   20.491161]:0 LTT : State dump init
[   20.493829]:0 LTT : ltt-kprobes init

This confirm that the modules are loaded I think.
Debugging the kernel a bit I realized that the function "int
ltt_channels_register(const char *name)"
is called only for the channel "metadata".
Do you think to any reason why other channels are not registered?

Thanks,

Alessandro



From:	Mathieu Desnoyers <compudj at krystal.dyndns.org>
To:	Alessandro Morari/Watson/Contr/IBM at IBMUS
Cc:	ltt-dev at lists.casi.polymtl.ca
Date:	12/10/2010 04:22 PM
Subject:	Re: [ltt-dev] no channel available - IBM BlueGene cluster




* Alessandro Morari (amorari at us.ibm.com) wrote:
>
> Hi,
>
> I'm installing LTTng on a BlueGene/P cluster, with Linux 2.6.29.1,
> patch-2.6.29.1-lttng-0.124 and ltt-control-0.75-15112-2009.
> After installing the patch and compiling the daemon, I run:

First make sure all the LTTng probe modules are loaded, and also ensure
that you run "ltt-armall" before using lttctl.

Please refer to the LTTng Manual on the lttng.org website for details.

Thanks,

Mathieu

>
> > lttctl -C -w ~/trace1 trace1
> And I obtain:
> >Linux Trace Toolkit Trace Control 0.75-15112009
> >
> >Controlling trace : trace1
> >
> >lttctl: Creating trace
> >lttctl: Forking lttd
> >Linux Trace Toolkit Trace Daemon 0.75-15112009
> >
> >Reading from debugfs directory : /mnt/debugfs/ltt/trace1
> >Writing to trace directory : /root/trace1
> >
> >lttctl: Starting trace
> and then I do the command:
> >lttctl -D -w ~/trace1 trace1
> and I obtain :
> >Linux Trace Toolkit Trace Control 0.75-15112009
> >
> >Controlling trace : trace1
> >
> >lttctl: Pausing trace
> >lttctl: Forking lttd
> >Linux Trace Toolkit Trace Daemon 0.75-15112009
> >
> >Reading from debugfs directory : /mnt/debugfs/ltt/trace1
> >Writing to trace directory : /root/trace1
> >
> >No channel available for reading, exiting
> >lttd process running failed
> >
> >
> /mnt/debugfs/ltt/control/trace1/channel contains only the directory
> metadata
> I verified what happen inside the code and it seems that only the
> "metadata"
> channel exists.
>
> What may be the cause of the problem?
>
> Thanks,
>
> --
> Alessandro

> _______________________________________________
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> ltt-dev at lists.casi.polymtl.ca
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--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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