Re: [boost] [thread] Memory usage of threads on 64bit linux

Subject: Re: [boost] [thread] Memory usage of threads on 64bit linux
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2012-08-28 13:00:07

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#thread.thread_management.tutorial.attributes 
and
http://www.boost.org/doc/libs/1_51_0/doc/html/thread/thread_management.html#thread.thread_management.thread.attr_callable_constructor.

Best,
Vicente