[ltt-dev] lockdep trace

[Mathieu Desnoyers]

* Harald Gustafsson (hgu1972 at gmail.com) wrote:
> Hi,
> 
> I'm trying to trace all lock operations in the kernel for a project
> which involves deciding dependencies between tasks. I'm using lttng
> for the tracing and was expecting to see a huge amount of trace
> events, but I see none. So obviously I have configured something
> wrong.
> 
> The question is what kernel configs are needed to trace lockdep lock
> operations? And do I need any configurations when starting the
> tracing? I use ltt-armall with the -l option,

Sounds good. Which version of lttng are you using ?

> I have the module
> lockdep_trace inserted (any module parameters?).

Should be fine without parameter.

> I have installed
> lttng using the ubuntu packages available in ppa. I have verified that
> all the markers under lockdep in debugfs are enabled, i.e. return 1.
> Other markers produce traces.

In your kernel config, under the "Kernel Hacking" menu, did you enable
the options related to lock dependency debug, and lock proving and so
on ? You should ensure that CONFIG_LOCKDEP is selected in your kernel
config file.

Thanks,

Mathieu

> 
> Regards,
>  Harald Gustafsson
> 
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-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com