Re: 13.0 RC4 might be delayed

> On Mon, Mar 29, 2021 at 4:37 AM David G Lawrence via freebsd-current <
> freebsd-current_at_freebsd.org> wrote:
> 
> > > > On 27/03/21 06:04, David G Lawrence via freebsd-current wrote:
> > > >>> On Fri, Mar 26, 2021 at 1:01 PM Graham Perrin <
> > grahamperrin_at_gmail.com>
> > > >>> wrote:
> > > >>>
> > > >>>> On 26/03/2021 03:40, The Doctor via freebsd-current wrote:
> > > >>>>> ??? if people are having issues with ports like ???
> > > >>>>
> > > >>>> If I'm not mistaken:
> > > >>>>
> > > >>>> * 13.0-RC3 seems to be troublesome, as a guest machine, with
> > > >>>> emulators/virtualbox-ose 6.1.18 as the host
> > > >>>>
> > > >>>> * no such trouble with 12.0-RELEASE-p5 as a guest.
> > > >>>>
> > > >>>> I hope to refine the bug report this weekend.
> > > >>>>
> > > >>>
> > > >>> Had nothing but frequent guest lockups on 6.1.18 with my Win7
> > system.
> > > >>> That
> > > >>> was right after 6.1.18 was put into ports. Fell back to legacy (v5)
> > and
> > > >>> will try again shortly to see if it's any better.
> > > >>
> > > >> Kevin,
> > > >>
> > > >> ?????? Make sure you have these options in your /etc/sysctl.conf :
> > > >>
> > > >> vfs.aio.max_buf_aio=8192
> > > >> vfs.aio.max_aio_queue_per_proc=65536
> > > >> vfs.aio.max_aio_per_proc=8192
> > > >> vfs.aio.max_aio_queue=65536
> > > >>
> > > >> ?????? ...otherwise the guest I/O will random hang in VirtualBox.
> > This
> > > >> issue was
> > > >> mitigated in a late 5.x VirtualBox by patching to not use AIO, but
> > the
> > > >> issue
> > > >> came back in 6.x when that patch wasn't carried forward.
> > > >
> > > > Sorry I lost that patch. Can you point me to the patch? Maybe it can
> > be
> > > > easily ported.
> > > >
> > >
> > > I found the relevant commit. Please give me some time for testing and
> > > I'll put this patch back in the tree.
> >
> >    If you're going to put that patch back in, then AIO should probably be
> > made an option in the port config, as shutting AIO off by default will
> > have a significant performance impact. Without AIO, all guest IO will
> > be become synchronous.
> >
> 
> Are you sure about that? Without AIO, VBox uses a generic POSIX backend,
> which is based on pthread, I think.

   No, I'm not sure - I haven't looked at the code. My comment is based on
some comments that a VirtualBox developer made in a forum 3-4 years ago
where he said that the "generic POSIX" IO was very simple and never
intended to be used in production - only as a placeholder when developing
for a new host platform.

   Are you sure that it does multi-threaded IO?

-DG