sure, I will report this to GCC community.
At 2014-07-08 02:58:48, "Antony Polukhin"
What if you try with just 1 integer? Does the difference in time stay proportionally the same? There won't be big differences if there is just 1 integer. So this proofs that it could be a memory copy problem.
I'd run the example code through Callgrind (valgrind --tool=callgrind) and then compare the reports in KCachegrind. This should at least give you an idea of the source of the problem. You are right. I ran callgrind, and it showed some interesting things. If I compiled without C++11, it shows the most hot spot is "wordcopy_fwd_align". Otherwise, the most hotspot is "boost::bind" and there is no records for wordcopy_fwd_align. I think that means if we dont' use C++11, there will be some memory copy optimizations.
Maybe trying another compiler would help you obtain your "proof". How about intel compiler? It also has the "-std=c++11" flag, so, if it is a compiler issue it will be clear. As you suggested, I tried Intel compiler. It's great. The data shows there is no performance differences between with or without C++11 in boost::function. That proofs your guess that it's a compiler issue.
So here is my conclusion, there won't be memory copy optimization when using (C++11, boost::function, gcc4.9/clang3.4). But Intel compiler does well to do C++11 related optimizations. Could you please create a ticket in GCC's bugzilla for this issue? Post the most interesting parts of this discussion in that ticket and then post a link to the ticket in this mailing list. Thanks in advance! -- Best regards, Antony Polukhin