http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59439
--- Comment #4 from Ben Maurer <ben.maurer at gmail dot com> ---
Also, here's where perf says time is being spent. While only 25% is shown as
being in the locale constructor/destructor, I suspect that the time spent in
other methods is actually related to the ping-ponging of cachelines caused by
the constructor -- all the time is being spent in memory access which should be
very hot in the CPU cache.
16.77% benchmark libstdc++.so.6.0.18 [.] std::locale::locale()
10.42% benchmark libstdc++.so.6.0.18 [.] std::locale::~locale()
9.93% benchmark libstdc++.so.6.0.18 [.] bool
std::has_facet<std::num_put<char, std::ostreambuf_iterator<char,
std::char_traits<char> > > >(std::locale const&)
9.84% benchmark libstdc++.so.6.0.18 [.] std::num_put<char,
std::ostreambuf_iterator<char, std::char_traits<char> > > const&
std::use_facet<std::num_put<char, std::ostreambuf_iterator<char,
std::char_traits<char> > > >(std::locale const&)
9.26% benchmark libstdc++.so.6.0.18 [.] bool
std::has_facet<std::num_get<char, std::istreambuf_iterator<char,
std::char_traits<char> > > >(std::locale const&)
9.10% benchmark libstdc++.so.6.0.18 [.] std::num_get<char,
std::istreambuf_iterator<char, std::char_traits<char> > > const&
std::use_facet<std::num_get<char, std::istreambuf_iterator<char,
std::char_traits<char> > > >(std::locale const&)
8.78% benchmark libstdc++.so.6.0.18 [.] std::ctype<char> const&
std::use_facet<std::ctype<char> >(std::locale const&)
6.14% benchmark libstdc++.so.6.0.18 [.]
std::locale::operator=(std::locale const&)
3.71% benchmark libstdc++.so.6.0.18 [.]
std::__use_cache<std::__numpunct_cache<char> >::operator()(std::locale const&)
const
3.66% benchmark libstdc++.so.6.0.18 [.] bool
std::has_facet<std::ctype<char> >(std::locale const&)
3.42% benchmark libstdc++.so.6.0.18 [.] __dynamic_cast
1.96% benchmark libstdc++.so.6.0.18 [.] std::locale::id::_M_id() const
0.89% benchmark benchmark [.] doIoStream()
