[ltt-dev] lockdep trace

[Mathieu Desnoyers]

* Harald Gustafsson (hgu1972 at gmail.com) wrote:
> > Sounds good. Which version of lttng are you using ?
> I have tried this both on my x86 machine using the ubuntu ppa package
> which uses kernel 2.6.35-24 and to me unknown lttng version. But I
> also tried this on a ARM development board with kernel 2.6.34 and
> lttng version 0.221 without success.
> 
> > 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.
> 
> In the ubuntu-ppa lttng package only LOCKDEP_SUPPORT is enabled, not
> LOCKDEP and not LOCKDEP_DEBUG, neither DEBUG_LOCK_ALLOC,
> PROVE_LOCKING, LOCK_STAT or any of the
> INLINE_{READ|WRITE|SPIN}_LOCK_*. The same configuration have been used
> on the ARM board.
> 
> Hence, I should enable LOCKDEP, LOCKDEP_DEBUG, DEBUG_LOCK_ALLOC and
> PROVE_LOCKING.

PROVE_LOCKING might not be needed (and is quite heavyweight), but yes,
enabling at the very least LOCKDEP is needed.

Thanks,

Mathieu

> 
> Thanks,
>  Harald
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com