Memory coherency issue with IO thread offloading?

[Michael Ellerman]

Jens Axboe <axboe at kernel.dk> writes:
> On 3/24/23 1:27?AM, Christophe Leroy wrote:
>> Le 23/03/2023 ? 19:54, Jens Axboe a ?crit :
>>> I got a report sent to me from mariadb, in where 5.10.158 works fine and
>>> 5.10.162 is broken. And in fact, current 6.3-rc also fails the test
>>> case. Beware that this email is long, as I'm trying to include
>>> everything that may be relevant...
>> 
>> Which variant of powerpc ? 32 or 64 bits ? Book3S or BookE ?
>
> I knew I'd forget something important... It's power9:
>
> processor	: 0
> cpu		: POWER9 (architected), altivec supported
> clock		: 2200.000000MHz
> revision	: 2.2 (pvr 004e 1202)

Believe it or not there's still more variables in play, Power9 has two
different MMUs, and Linux can run on two different hypervisors as well
as on bare metal P9 :)

Can you paste the last ~10 lines of /proc/cpuinfo, with the "machine",
"firmware" and "MMU" lines, that should tell us everything we need to
know.

cheers