On Wed, Jan 6, 2021 at 9:21 PM Kevin Fenzi <kevin(a)scrye.com> wrote:
On Wed, Jan 06, 2021 at 02:11:37PM +0100, Daniel Pocock wrote:
> We did some more troubleshooting of AMD Radeon issues on ppc64
Small aside: I know you mean ppc64le (because thats all we make
anymore), but it confuses me since 'ppc64' is what we called the old big
endian 64 bit ppc, which is retired. Can I ask you to please use
'ppc64le' when talking about the current thing? :)
> As with Nouveau, it looks like a change from 64k to 4k page size got it
> working again with RX 5700. I suspect it will be similar for RX 6800 if
> we can get some of them, they are a good complement for the compute power.
> The issue is page size, not ppc64
> Vikings in Germany are about to launch their European Talos II
> workstations so there will be more users and many will want to try
> Fedora as this is the place to get newest versions of stuff.
> How would people feel about making 4k the default page size for
> workstation users?
> Given that the default file system, Btrfs, is sensitive to page size and
> there are not so many GPUs outside of those vendors mentioned above, I
> feel this is a compelling issue.
I don't have any great opinion on changing it, but hopefully a few power
folks will chime in with thoughts. Would this only need to be changed in
It is just kernel, there was a bunch of work done in the toolchain for
aarch64 to ensure support here, one of the mass rebuilds around F-23
sorted the problem out.
We started aarch64 for 64K page sizes, which RHEL 7/8 still use, but
due to devices like Raspberry Pi and the way the CMA allocations work
on that arch meant we lost 512Mb of RAM, not sure if POWER (and I'm
referring to both endians here) either uses CMA or has the same issue,
we moved to 4K page sizes.
Ultimately it's software bugs and if the software is open it's a
fixable problem. Are there bugs filed? Because I've always found the
IBM team that are involved in Fedora are pretty active on addressing
those sorts of problems.