Re: [Valgrind-users] memory barriers support

[David F. <fa...@kd...>]

On Tuesday 19 August 2014 21:57:02 Philippe Waroquiers wrote:
> On Tue, 2014-08-19 at 21:44 +0200, David Faure wrote:
> > On Tuesday 19 August 2014 21:00:58 Philippe Waroquiers wrote:
> > > On Tue, 2014-08-19 at 16:46 +0200, Roland Mainz wrote:
> > > > > ThreadSanitizer won't comprehend the fence instructions inserted by
> > > > > urcu.
> > > > > I believe even Helgrind won't, because these instructions do not
> > > > > imply
> > > > > any happens-before relation.
> > > > 
> > > > Is there any opensource or commercial tool which might help in such
> > > > situations (e.g. problems with memory barriers) ?
> > > 
> > > helgrind or drd or ThreadSanitizer could still be used for race
> > > condition detection but you would have to annotate either the rcu
> > > library or the calling code to describe the happens before
> > > relationships.
> > 
> > Are such annotations documented somewhere?
> 
> http://www.valgrind.org/docs/manual/hg-manual.html#hg-manual.client-requests
> gives a list of such annotations, and points to helgrind.h for more
> information.

Thanks.

> > I'm still trying to find a way to annotate threadsafe-statics so that
> > helgrind doesn't complain about them.
> 
> What is a threadsafe-static ?

See older mail to this list, attached.

It doesn't use __thread anywhere, but rather lets gcc take care of ensuring 
thread-safety on static objects (like C++11 mandates, but it has been doing so 
for a long time already).

Is that related to nptl (I'm not sure what that is exactly)?

-- 
David Faure, fa...@kd..., http://www.davidfaure.fr
Working on KDE Frameworks 5