Re: 2026 TODO list!

----- Original Message -----
> From: "jhibbits" <jhibbits@FreeBSD.org>
> To: "Timothy Pearson" <tpearson@raptorengineering.com>
> Cc: "Lexi Winter" <ivy@freebsd.org>, "freebsd-ppc" <freebsd-ppc@freebsd.org>
> Sent: Tuesday, January 13, 2026 4:44:32 PM
> Subject: Re: 2026 TODO list!

> On Tue, 13 Jan 2026 15:27:05 -0600 (CST)
> Timothy Pearson <tpearson@raptorengineering.com> wrote:
> 
>> ----- Original Message -----
>> > From: "Lexi Winter" <ivy@freebsd.org>
>> > To: "freebsd-ppc" <freebsd-ppc@freebsd.org>
>> > Sent: Tuesday, January 13, 2026 3:42:28 AM
>> > Subject: Re: 2026 TODO list!
>> 
>> > Adrian Chadd wrote in
>> > <CAJ-VmonYHdVhdPiaLHUqzPv33_iAGiTY=_hGrhg4rXF5+YZPQQ@mail.gmail.com>:
>> >  
>> >> I'd like to assemble a 2026 TODO list for PPC64 work. Justin, Ivy,
>> >> Warner, I and and others have been poking at the sharp edges and
>> >> trying to use/abuse various PPC64 hardware and VMs.
>> >> 
>> >> I'd appreciate some brainstorming from y'all about what you'd like
>> >> to see fixed, implemented and working.
>> > 
>> > i've been meaning to look at making lldb work on powerpc64le for
>> > both kernel and userland debugging.  this looks like it should be
>> > pretty simple, since it already supports FreeBSD/ppc64 and
>> > Linux/ppc64le, so it's just a matter of combining the two.
>> > 
>> > i've been busy with non-FreeBSD stuff recently but i'm hoping i can
>> > look at this soon.
>> > 
>> > Raptor has kindly given me access to a Talos II so i can do dev work
>> > and also test patches there if needed.
>> > 
>> > a couple of other things i think are important:
>> > 
>> > - non-OpenFirmware ppc64le loader - i see a couple of people have
>> >  already mentioned this.
>> > 
>> > - SMP performance is quite bad; this 44-core SMT4 Talos II runs
>> >  buildworld at the same speed as my 8-core 2.6GHz Xeon system.
>> >  i mentioned this to Justin and he suspects this could be from
>> >   locking issues in vm/pmap.
>> 
>> After digging around in the PCI driver for the past month, I think
>> we're also not getting DMA enabled on potentially *any* PCI devices.
>> It looks like the DMA tag was removed for PHB4 (POWER9) support, but
>> it might have worked on PHB3 (POWER8).  Once I finish fixing the rest
>> of the PE 1:1 mapping mess I'll start looking at that and see if we
>> can't get DMA reenabled -- no DMA would definitely explain poor
>> performance on disk intensive activity...
>> 
> 
> DMA should be active already.  Without a bus tag it defaults to nexus,
> which allows all as 1:1, so no translation, restrictions, or anything
> like that.  Also no IOMMU is attached.

Oh, interesting, didn't know that.  Thanks for the info! :)