[Boost-bugs] [Boost C++ Libraries] #4780: Many deadline_timer objects triggers worst-case vector reallocation in timer_queue

Subject: [Boost-bugs] [Boost C++ Libraries] #4780: Many deadline_timer objects triggers worst-case vector reallocation in timer_queue
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-10-24 01:56:07

#4780: Many deadline_timer objects triggers worst-case vector reallocation in
timer_queue
------------------------------+---------------------------------------------
 Reporter:  chris_kohlhoff    |       Owner:  chris_kohlhoff
     Type:  Bugs              |      Status:  new           
Milestone:  To Be Determined  |   Component:  asio          
  Version:  Boost 1.44.0      |    Severity:  Problem       
 Keywords:                    |  
------------------------------+---------------------------------------------
 Using the g++ 4.4.5 on linux x86_64, the following program:

 {{{
 #include <boost/asio/deadline_timer.hpp>

 boost::asio::io_service io_service;

 struct timer
 {
   boost::asio::deadline_timer t;
   timer() : t(io_service) {}
 } timers[100000];

 void handler(boost::system::error_code) {}

 int main()
 {
   for (std::size_t i = 0; i < 100000; ++i)
   {
     timers[i].t.expires_from_now(boost::posix_time::seconds(1000));
     timers[i].t.async_wait(handler);
   }
 }
 }}}

 takes a very long time to run:

 {{{
 $ time ./a.out

 real    0m48.504s
 user    0m21.469s
 sys     0m27.038s
 }}}

 This is due to the vector<>-based heap in asio::detail::timer_queue
 reserve()-ing one element at a time.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4780>
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