[Bug 203682] Slow boot under VMware Fusion w/ UEFI firmware and SMP -- until APs are launched

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=203682

--- Comment #8 from John Baldwin <jhb at FreeBSD.org> ---
The problem with monitor/mwait is that it has to be emulated by the hypervisor
(you get a VM-exit for it), but that's actually hard to do because the
hypervisor can't tell when the relevant line is going to be updated (I'm pretty
sure that bhyve just returns immediately from mwait for example).  We can
however put the APs to sleep while spinning on aps_ready via hlt and use an IPI
to resume them.  This should work with most if not all hypervisors.  That said,
I do plan to enable EARLY_AP_STARTUP in 12 anyway (perhaps I'll do it at the
vendor summit later this week).

-- 
You are receiving this mail because:
You are the assignee for the bug.