Re: [boost] [Interprocess] barrier_test hanging on Apple PowerPC

From: atack2_at_[hidden]
Date: 2007-08-21 15:58:09

I remember fixing another PPC atomics.hpp issue a while ago, I'll look at it 
tonight.

Where can I read about running the tests? I've not played with that before.

--
Tack
---- Original message ----
>Date: Tue, 21 Aug 2007 21:33:30 +0200
>From: Ion Gaztañaga <igaztanaga_at_[hidden]>  
>Subject: Re: [boost] [Interprocess] barrier_test hanging on Apple PowerPC  
>To: "boost_at_[hidden]" <boost_at_[hidden]>
>
>Doug Gregor wrote:
>> The problem only seems to occur on PowerPC Mac, because the test is  
>> running fine on my Intel Mac. There's a gdb dump of the backtraces  
>> for all running threads below.
>
>Removed from SVN.
>
>The main problem is that Mac does not have process-shared 
>barrier/mutexes/condition variables and an emulation using spinlocks is 
>used. Since my knowledge about atomic operations is *zero* my 
>implementation of interprocess_condition might be wrong or just the 
>atomic operations I'm using are not correctly implemented.
>
>I guess I should ask Boost thread-experts (Boost.Thread maintainers 
>willing to help?) to write these synchronization primitives for me 
>or/and beg for a simple atomic operation package in Boost. At least some 
>that implement increment, cas, decrement, atomic read and read (full 
>barrier semantics are enough for me, I just don't understand what 
>acquire and release are ;-) ).
>
>The implementation of the emulated barrier is pretty simple:
>
>inline barrier::barrier(unsigned int count)
>    : m_threshold(count), m_count(count), m_generation(0)
>{
>    if (count == 0)
>       throw std::invalid_argument("count cannot be zero.");
>}
>
>inline bool barrier::wait()
>{
>    scoped_lock<interprocess_mutex> lock(m_mutex);
>    unsigned int gen = m_generation;
>
>    if (--m_count == 0){
>       m_generation++;
>       m_count = m_threshold;
>       m_cond.notify_all();
>       return true;
>    }
>
>    while (gen == m_generation){
>       m_cond.wait(lock);
>    }
>    return false;
>}
>
>so I guess there is problem with my emulated condition implementation or 
>with atomic operations (which are taken from apache run-time library).
>
>Regards,
>
>Ion
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