Re: [Valgrind-developers] detection of inter-thread dependencies trough condition variables

[Konstantin S. <kon...@gm...>]

On Fri, Nov 6, 2009 at 10:26 AM, Bart Van Assche
<bar...@gm...>wrote:

> On Thu, Nov 5, 2009 at 11:38 PM, ERSEK Laszlo <la...@ca...>
> wrote:
> > On Thu, 5 Nov 2009, Bart Van Assche wrote:
> >
> >> Can you please post a small self-standing program or comment on
> >> Konstantin's test program
> >> (
> http://code.google.com/p/data-race-test/source/browse/trunk/unittest/racecheck_unittest.cc#520
> )
> >> ? I prefer commenting on a program that can be compiled and run instead
> >> of commenting on incomplete program fragments.
> >
> > Konstantin didn't get the false positives described in the manual. What I
> > proposed is only for the case when there's a false positive to avert, so
> > if there's no false positive then my proposition is automatically void.
> >
> > I installed valgrind-3.5.0 from source and wrote a small program:
> >
> > http://pastebin.com/f6a4181c2
>
> Regarding the test program: the pointer-to-integer 'protected' is
> properly protected by locking, and the code that writes a value to
> *protected and the code that reads *protected is synchronized via the
> producer-consumer pattern. Helgrind and DRD will implicitly insert a
> happens-before arc between the producer and consumer, but
> ThreadSanitizer not.


ThreadSanitizer in the pure happens-before mode (--pure-happens-before=yes,
NOT default) will behave exactly like Helgrind and DRD (see my previous
reply).


> I believe that Konstantin proposed the
> ANNOTATE_PCQ_*()

These will work, but there is a separate annotation specifically for cond
var case.
http://code.google.com/p/data-race-test/wiki/DynamicAnnotations#pthread_cond_wait_loop



> annotations some time ago in order to allow explicit
> annotation of the producer-consumer pattern in source code (see also
> http://article.gmane.org/gmane.comp.debugging.valgrind.devel/8398).
>
> P.S.: please use reply-all and don't modify the CC-list when replying.
>
> Bart.
>