Re: [boost] [Lockfree review] Meta-comments

Subject: Re: [boost] [Lockfree review] Meta-comments
From: Tim Blechmann (tim_at_[hidden])
Date: 2011-07-26 17:14:26

> >> Matt, how have you measured the stability?  One of my main concerns
> >> with Atomic is that it seems to lack any tests, so it is hard to know
> >> whether it is actually working correctly or not.  (Doing the correct
> >> operation but non-atomically, or without the required memory barriers,
> >> would often appear to work perfectly.)
> > 
> > well, i am not sure, whether it can be tested for full correctness. i
> > suppose all we can do is to compile-tests, for the rest we would have to
> > review the code.
> 
> At the very least, you can e.g. run two threads that inc and dec a
> shared atomic variable and verify that you get the expected answer.
> I'm sure that someone with some experience in this area would have many
> more ideas.

in this case, one will have atomic operations

> > * gcc-4.6 (and probably earlier) cannot compile boost.lockfree with
> > std::atomic
> > 
> >   i suspect, their implementation is still incomplete
> 
> Can you tell us more about that?  Perhaps it points to an issue with
> boost.lockfree that reviewers might be interested in.

many undefined references to std::atomic members:

queue.cpp:(.text+0x48): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::load(std::memory_order) const'
queue.cpp:(.text+0x9f): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>&, 
boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>, std::memory_order)'
queue.cpp:(.text+0xc4): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0xed): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::store(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:(.text+0x106): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x11c): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x135): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x176): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::compare_exchange_strong(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>&, boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:(.text+0x1af): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>&, boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:(.text+0x1e5): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::compare_exchange_strong(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>&, boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
CMakeFiles/queue.dir/queue.cpp.o: In function `consumer()':
queue.cpp:(.text+0x24e): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x26c): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x282): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x29b): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x2f8): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>&, boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:(.text+0x31b): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::load(std::memory_order) const'
queue.cpp:(.text+0x369): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>&, 
boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>, std::memory_order)'
queue.cpp:(.text+0x3c4): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::compare_exchange_strong(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>&, boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:(.text+0x3ea): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x3fe): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x415): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x42c): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:(.text+0x493): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>&, boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:(.text+0x4b7): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::load(std::memory_order) const'
queue.cpp:(.text+0x50f): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>&, 
boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>, std::memory_order)'
queue.cpp:(.text+0x566): undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> 
>::compare_exchange_strong(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>&, boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node>, std::memory_order)'
CMakeFiles/queue.dir/queue.cpp.o: In function `main':
queue.cpp:(.text.startup+0x39): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::is_lock_free() const'
queue.cpp:(.text.startup+0xad4): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::is_lock_free() const'
queue.cpp:(.text.startup+0xae6): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::is_lock_free() const'
CMakeFiles/queue.dir/queue.cpp.o: In function `_GLOBAL__sub_I_producer_count':
queue.cpp:(.text.startup+0x145f): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::store(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:(.text.startup+0x1478): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::store(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node>, std::memory_order)'
CMakeFiles/queue.dir/queue.cpp.o: In function `boost::lockfree::detail::freelist_stack<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node, false, std::allocator<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::~freelist_stack()':
queue.cpp:
(.text._ZN5boost8lockfree6detail14freelist_stackINS0_5queueIiNS_9parameter5void_ES5_E4nodeELb0ESaIS7_EED2Ev[_ZN5boost8lockfree6detail14freelist_stackINS0_5queueIiNS_9parameter5void_ES5_E4nodeELb0ESaIS7_EED5Ev]+0x16): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::operator 
boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>() const'
CMakeFiles/queue.dir/queue.cpp.o: In function `boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::~queue()':
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x23): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x36): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x54): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0xab): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::store(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0xbf): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x10f): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::store(boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>, std::memory_order)'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x148): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::store(boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node>, std::memory_order)'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x15a): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::queue<int, boost::parameter::void_, 
boost::parameter::void_>::node> >::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x17d): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x1dd): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>&, 
boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>, std::memory_order)'
queue.cpp:
(.text._ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED2Ev[_ZN5boost8lockfree5queueIiNS_9parameter5void_ES3_ED5Ev]+0x1f8): 
undefined reference to `std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::operator 
boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>() const'
CMakeFiles/queue.dir/queue.cpp.o: In function `boost::lockfree::detail::freelist_stack<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node, false, std::allocator<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::reserve_unsafe(unsigned long)':
queue.cpp:
(.text._ZN5boost8lockfree6detail14freelist_stackINS0_5queueIiNS_9parameter5void_ES5_E4nodeELb0ESaIS7_EE14reserve_unsafeEm[boost::lockfree::detail::freelist_stack<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node, false, std::allocator<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::reserve_unsafe(unsigned long)]+0x42): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree6detail14freelist_stackINS0_5queueIiNS_9parameter5void_ES5_E4nodeELb0ESaIS7_EE14reserve_unsafeEm[boost::lockfree::detail::freelist_stack<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node, false, std::allocator<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::reserve_unsafe(unsigned long)]+0x86): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::store(boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>, std::memory_order)'
CMakeFiles/queue.dir/queue.cpp.o: In function `boost::lockfree::detail::freelist_stack<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node, false, std::allocator<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::allocate()':
queue.cpp:
(.text._ZN5boost8lockfree6detail14freelist_stackINS0_5queueIiNS_9parameter5void_ES5_E4nodeELb0ESaIS7_EE8allocateEv[boost::lockfree::detail::freelist_stack<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node, false, std::allocator<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::allocate()]+0x1f): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> >::load(std::memory_order) const'
queue.cpp:
(.text._ZN5boost8lockfree6detail14freelist_stackINS0_5queueIiNS_9parameter5void_ES5_E4nodeELb0ESaIS7_EE8allocateEv[boost::lockfree::detail::freelist_stack<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node, false, std::allocator<boost::lockfree::queue<int, 
boost::parameter::void_, boost::parameter::void_>::node> >::allocate()]+0x66): undefined reference to 
`std::atomic<boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node> 
>::compare_exchange_weak(boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>&, 
boost::lockfree::detail::tagged_ptr<boost::lockfree::detail::freelist_node>, std::memory_order)'

cheers, tim