[Boost-bugs] [Boost C++ Libraries] #3765: unordered containers use malloc() for each insertion

Subject: [Boost-bugs] [Boost C++ Libraries] #3765: unordered containers use malloc() for each insertion
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-12-12 19:11:16

#3765: unordered containers use malloc() for each insertion
--------------------------------------------------+-------------------------
 Reporter:  Paul Pogonyshev <pogonyshev@…>        |       Owner:  danieljames 
     Type:  Bugs                                  |      Status:  new         
Milestone:  Boost 1.42.0                          |   Component:  unordered   
  Version:  Boost 1.41.0                          |    Severity:  Optimization
 Keywords:                                        |  
--------------------------------------------------+-------------------------
 At least with STL that comes with G++ 4.4, Boost.Unordered containers use
 malloc() on each insertion, which degrades performance.

 For example, with the attached trivial program I set a breakpoint on
 _int_malloc() in GDB and the second stacktrace looks this way:

 #0  _int_malloc (av=0xb7e853c0, bytes=8) at malloc.c:4275
 #1  0xb7db117e in *__GI___libc_malloc (bytes=8) at malloc.c:3660
 #2  0xb7f86167 in operator new(unsigned int) () from
 /usr/lib/libstdc++.so.6
 #3  0x08049c3c in
 __gnu_cxx::new_allocator<boost::unordered_detail::hash_table_data_unique_keys<std::allocator<int>
 >::node>::allocate(unsigned int, void const*) ()
 #4  0x080497ff in
 boost::unordered_detail::hash_table_data_unique_keys<std::allocator<int>
 >::node_constructor::construct_preamble() ()
 ...

 malloc() and friends are quite prominent in profile of my actual program
 as the result of the usage from boost::unordered_set.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3765>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.