Paolo Bonzini <pbonz...@redhat.com> writes: > Alex discovered that CMPXCHG128 was not enabled when building for > x86_64, resulting in slow execution for wide atomic instructions, > creating a huge contention when combined with a high number of cpus > (found while booting android aarch64 guest on x86_64 host). > > The problem is that even though we enable -mcx16 option for x86_64, this > is not used when testing for CMPXCHG128. Thus, we silently turn it off. > > x86_64 is the only architecture adding machine flags for now, so the > problem is limited to this host architecture. However, the problem > is generic, so define a new variable for all the -m options, so that > they can be used for other such tests in the future. > > Based-on: <20241004223715.1275428-1-pierrick.bouv...@linaro.org> > Supersedes: <20241004220123.978938-1-pierrick.bouv...@linaro.org>
Reviewed-by: Alex Bennée <alex.ben...@linaro.org> Tested-by: Alex Bennée <alex.ben...@linaro.org> -- Alex Bennée Virtualisation Tech Lead @ Linaro
