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

[Bart V. A. <bar...@gm...>]

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