Le 28/08/12 18:32, Phil Endecott a écrit :
Conrad Mercer wrote:
I have been using boost threads on 32bit linux for some time and am very happy with their performance so far. Recently the project was moved to a 64bit platform and we saw a huge increase in memory usage (from about 2.5gb to 16-17gb). I have done profiling and found that the boost threads are the source of the huge allocation. Each thread is allocating about 10x what it was doing on 32bit.
I profiled using valgrind's massif and have confirmed the issue using only boost threads in a separate test application. I also tried using std::threads instead and these do not exhibit the large memory allocation issue.
I believe that 32-bit Linux sets the default stack size to 2 MB, and much larger on 64-bit. So I would expect to see it using much more _virtual_ memory - but if you don't actually use it, then no physical memory is ever mapped to those pages and there is no performance or other concern.
A deficiency of Boost.Thread and std::thread is that they provide no way to change the stack size of new threads. This has been discussed a few times here. It is possible that the libstdc++ implementation of std::thread chooses to set a smaller default stack size.
Boost.Thread contains since Boost 1.50 a way to set thread attributes and in particular the stack size #2741 <http://svn.boost.org/trac/boost/ticket/2741> Proposal to manage portable and non portable thread attributes. See http://www.boost.org/doc/libs/1_51_0/doc/html/thread/thread_management.html#... and http://www.boost.org/doc/libs/1_51_0/doc/html/thread/thread_management.html#.... Best, Vicente