Messages in this thread | | | From | Punit Agrawal <> | Subject | Re: [RFC PATCH 2/4] cpufreq: acpi-cpufreq: Add processor to the ignore PSD override list | Date | Mon, 14 Dec 2020 22:27:09 +0900 |
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Borislav Petkov <bp@alien8.de> writes:
> On Sat, Dec 12, 2020 at 08:36:48AM +0900, Punit Agrawal wrote: >> To me it suggests, that there are likely more systems from the family >> that show the characteristic described below. > > Until we find a *single* system with a broken BIOS which has those > objects kaputt and then this heuristic would need an exception. > > VS the clear statement from AMD that from zen3 onwards, all BIOS will be > tested. I hope they boot Linux at least before they ship.
IIUC, this suggests that Linux booting on anything prior to Zen3 is down to pure luck - I hope that wasn't the case.
>> In all these systems, the override causes this topology information to >> be ignored - treating each core to be a separate domain. The proposed >> patch removes the override so that _PSD is taken into account. > > You're still not answering my question: what does the coupling of the > SMT threads bring on those systems? Power savings? Perf improvement? > Anything palpable or measurable?
At the moment acpi thermals is bust on this and other affected AMD system I have access to. That'll need fixing before any sensible measurements can be run.
Tbh, I didn't quite expect the patch to the PSD exclusion list to be so controversial - especially when a similar change for zen3 had recently been merged. If you're really not keen on the change, I will carry it locally for the time being and revisit once the other issues have been resolved.
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