[lttng-dev] Debian specific userspace RCU configure override

[Mathieu Desnoyers]

----- Original Message -----
> From: "Jon Bernard" <jbernard at debian.org>
> To: "Ondřej Surý" <ondrej at sury.org>
> Cc: "Mathieu Desnoyers" <mathieu.desnoyers at efficios.com>, "Michael Jeanson" <mjeanson at efficios.com>, "lttng-dev"
> <lttng-dev at lists.lttng.org>
> Sent: Tuesday, May 27, 2014 4:18:48 PM
> Subject: Re: Debian specific userspace RCU configure override
> 
> * Ondřej Surý <ondrej at sury.org> wrote:
> > On Sun, May 25, 2014, at 2:59, Mathieu Desnoyers wrote:
> > > Why are each package compiled against completely different targets ?
> > 
> > urcu invokes ./configure manually while ltt-control uses
> > dh_auto_configure wrapper and that makes the difference
> 
> This is correct.  When I first saw the difference, I assumed they would
> both invoke configure in a way that wouldn't effect the target.  But now
> I remember having a similar problem on sparc (which is why urcu includes
> this override) where the target discovery was not correct.
> 
> It looks to me like a bug related to debhelper (which provides
> dh_auto_configure).  For now, I think this override applied to
> lttng-tools will correctly fix the build without disabling dmb.  I will
> let the existing transition into testing complete and then submit new
> packages.

The big question here: is it OK to generate "dmb" instruction ? If the
intent of this architecture support is to cover earlier-than-armv7 ARM
processors, then "dmb" should not be explicitly generated, and therefore
URCU configuration would need fixing. If the intent of this Debian arch
is to cover only ARMv7 and better, then it's lttng-tools that needs
fixing.

Thoughts ?

Thanks,

Mathieu

> 
> --
> Jon
> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com