On 02/11/14 09:26, Justin T. Gibbs wrote: > On Jan 29, 2014, at 8:28 AM, Karl Pielorz <kpielorz_...@tdx.co.uk> wrote: >> The man page for xen (man 4 xen) states you should have: >> >> options NO_ADAPTIVE_MUTEXES >> options NO_ADAPTIVE_RWLOCKS >> options NO_ADAPTIVE_SX > > The “NO_ADAPTIVE” settings are an optimization when running in environments > where different guests run on the same physical CPU. However, many cloud > providers seem to statically pin CPUs to VMs, which means the adaptive lock > optimization works as expected.
... and with static pinning, adding the NO_ADAPTIVE_FOO options causes a significant drop in performance, so you really don't want them unless you're going to be sharing CPUs. -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid _______________________________________________ freebsd-xen@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-xen To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org"
