[Bug 271826] FreeBSD is disastrously slow on a PowerMac G5, freezing at every command

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=271826

--- Comment #35 from Mitch <mitch_com@hotmail.com> ---
(In reply to Justin Hibbits from comment #33)

Yesterday I've tried Ben's patch and my machine was way happier, unfortunately
the same problem still occurs, just less often.

I was able to install 14.1 and use it for a few minutes before the machine
crashed while idling.

Just trying to understand why we'd want to use memory barriers with the
powermac_smp_timebase_sync function.

Is it because PPC is using a weak memory model which would be problematic in an
SMP context like explained below ?

https://preshing.com/20120710/memory-barriers-are-like-source-control-operations/
https://preshing.com/20120930/weak-vs-strong-memory-models/

You mentioned that the code is derived from mpc85xx, do we have such a machine
in the field which is running a modern release properly ?

Also how was FreeBSD handling timebase sync before the introduction of
plateform_powermac ?

I'll try your suggestions and test it again.

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