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Date:      Tue, 13 Jan 2026 15:27:05 -0600 (CST)
From:      Timothy Pearson <tpearson@raptorengineering.com>
To:        Lexi Winter <ivy@freebsd.org>
Cc:        freebsd-ppc <freebsd-ppc@freebsd.org>
Subject:   Re: 2026 TODO list!
Message-ID:  <347736550.201698.1768339625331.JavaMail.zimbra@raptorengineeringinc.com>
In-Reply-To: <aWYThFQ8ODI9P0ml@amaryllis.le-fay.org>
References:  <CAJ-VmonYHdVhdPiaLHUqzPv33_iAGiTY=_hGrhg4rXF5%2BYZPQQ@mail.gmail.com> <aWYThFQ8ODI9P0ml@amaryllis.le-fay.org>

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----- 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...


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