http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51618
Bug #: 51618 Summary: synchronous futures are slow Classification: Unclassified Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: d...@boostpro.com Created attachment 26133 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26133 demo The attached program demonstrates; if you compile with -DNO_SYNCHRONOUS_FUTURE it will run much faster. I don't know if this should be considered a performance bug or not, but it seems to me that in principle it should be possible to make synchronous futures much faster than that; they could type-erase an object with no attached synchronization, right?