https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59439
--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> --- The testcase now scales with the number of CPUs, instead of running effectively single-threaded. If the global locale is changed so std::locale() != std::locale::classic() then every thread contends for the reference count on the global locale again. That would be mitigated by PR 71430.
